diff --git a/app/lib/bundler.js b/app/lib/bundler.js
index b2a8be4245..d4870c527a 100644
--- a/app/lib/bundler.js
+++ b/app/lib/bundler.js
@@ -78,7 +78,9 @@ var PackageInstance = function (pkg, bundle) {
     // anonymous packages you want to use (eg, app packages)
     use: function (names, where) {
       if (!(names instanceof Array))
-        names = [names];
+        names = names ? [names] : [];
+      if (!(where instanceof Array))
+        where = where ? [where] : [];
 
       _.each(names, function (name) {
         var pkg = packages.get(name);
@@ -88,9 +90,9 @@ var PackageInstance = function (pkg, bundle) {
 
     add_files: function (paths, where) {
       if (!(paths instanceof Array))
-        paths = [paths];
+        paths = paths ? [paths] : [];
       if (!(where instanceof Array))
-        where = [where];
+        where = where ? [where] : [];
 
       _.each(where, function (w) {
         _.each(paths, function (rel_path) {
diff --git a/app/lib/third/underscore.js b/app/lib/third/underscore.js
index 4f56013259..208d4cd890 100644
--- a/app/lib/third/underscore.js
+++ b/app/lib/third/underscore.js
@@ -1,5 +1,5 @@
-//     Underscore.js 1.1.7
-//     (c) 2011 Jeremy Ashkenas, DocumentCloud Inc.
+//     Underscore.js 1.3.1
+//     (c) 2009-2012 Jeremy Ashkenas, DocumentCloud Inc.
 //     Underscore is freely distributable under the MIT license.
 //     Portions of Underscore are inspired or borrowed from Prototype,
 //     Oliver Steele's Functional, and John Resig's Micro-Templating.
@@ -48,19 +48,21 @@
   // Create a safe reference to the Underscore object for use below.
   var _ = function(obj) { return new wrapper(obj); };
 
-  // Export the Underscore object for **CommonJS**, with backwards-compatibility
-  // for the old `require()` API. If we're not in CommonJS, add `_` to the
-  // global object.
-  if (typeof module !== 'undefined' && module.exports) {
-    module.exports = _;
-    _._ = _;
+  // Export the Underscore object for **Node.js**, with
+  // backwards-compatibility for the old `require()` API. If we're in
+  // the browser, add `_` as a global object via a string identifier,
+  // for Closure Compiler "advanced" mode.
+  if (typeof exports !== 'undefined') {
+    if (typeof module !== 'undefined' && module.exports) {
+      exports = module.exports = _;
+    }
+    exports._ = _;
   } else {
-    // Exported as a string, for Closure Compiler "advanced" mode.
     root['_'] = _;
   }
 
   // Current version.
-  _.VERSION = '1.1.7';
+  _.VERSION = '1.3.1';
 
   // Collection Functions
   // --------------------
@@ -78,7 +80,7 @@
       }
     } else {
       for (var key in obj) {
-        if (hasOwnProperty.call(obj, key)) {
+        if (_.has(obj, key)) {
           if (iterator.call(context, obj[key], key, obj) === breaker) return;
         }
       }
@@ -87,20 +89,21 @@
 
   // Return the results of applying the iterator to each element.
   // Delegates to **ECMAScript 5**'s native `map` if available.
-  _.map = function(obj, iterator, context) {
+  _.map = _.collect = function(obj, iterator, context) {
     var results = [];
     if (obj == null) return results;
     if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context);
     each(obj, function(value, index, list) {
       results[results.length] = iterator.call(context, value, index, list);
     });
+    if (obj.length === +obj.length) results.length = obj.length;
     return results;
   };
 
   // **Reduce** builds up a single result from a list of values, aka `inject`,
   // or `foldl`. Delegates to **ECMAScript 5**'s native `reduce` if available.
   _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) {
-    var initial = memo !== void 0;
+    var initial = arguments.length > 2;
     if (obj == null) obj = [];
     if (nativeReduce && obj.reduce === nativeReduce) {
       if (context) iterator = _.bind(iterator, context);
@@ -114,20 +117,22 @@
         memo = iterator.call(context, memo, value, index, list);
       }
     });
-    if (!initial) throw new TypeError("Reduce of empty array with no initial value");
+    if (!initial) throw new TypeError('Reduce of empty array with no initial value');
     return memo;
   };
 
   // The right-associative version of reduce, also known as `foldr`.
   // Delegates to **ECMAScript 5**'s native `reduceRight` if available.
   _.reduceRight = _.foldr = function(obj, iterator, memo, context) {
+    var initial = arguments.length > 2;
     if (obj == null) obj = [];
     if (nativeReduceRight && obj.reduceRight === nativeReduceRight) {
       if (context) iterator = _.bind(iterator, context);
-      return memo !== void 0 ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
+      return initial ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
     }
-    var reversed = (_.isArray(obj) ? obj.slice() : _.toArray(obj)).reverse();
-    return _.reduce(reversed, iterator, memo, context);
+    var reversed = _.toArray(obj).reverse();
+    if (context && !initial) iterator = _.bind(iterator, context);
+    return initial ? _.reduce(reversed, iterator, memo, context) : _.reduce(reversed, iterator);
   };
 
   // Return the first value which passes a truth test. Aliased as `detect`.
@@ -182,12 +187,12 @@
   // Delegates to **ECMAScript 5**'s native `some` if available.
   // Aliased as `any`.
   var any = _.some = _.any = function(obj, iterator, context) {
-    iterator = iterator || _.identity;
+    iterator || (iterator = _.identity);
     var result = false;
     if (obj == null) return result;
     if (nativeSome && obj.some === nativeSome) return obj.some(iterator, context);
     each(obj, function(value, index, list) {
-      if (result |= iterator.call(context, value, index, list)) return breaker;
+      if (result || (result = iterator.call(context, value, index, list))) return breaker;
     });
     return !!result;
   };
@@ -198,8 +203,8 @@
     var found = false;
     if (obj == null) return found;
     if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
-    any(obj, function(value) {
-      if (found = value === target) return true;
+    found = any(obj, function(value) {
+      return value === target;
     });
     return found;
   };
@@ -208,7 +213,7 @@
   _.invoke = function(obj, method) {
     var args = slice.call(arguments, 2);
     return _.map(obj, function(value) {
-      return (method.call ? method || value : value[method]).apply(value, args);
+      return (_.isFunction(method) ? method || value : value[method]).apply(value, args);
     });
   };
 
@@ -220,6 +225,7 @@
   // Return the maximum element or (element-based computation).
   _.max = function(obj, iterator, context) {
     if (!iterator && _.isArray(obj)) return Math.max.apply(Math, obj);
+    if (!iterator && _.isEmpty(obj)) return -Infinity;
     var result = {computed : -Infinity};
     each(obj, function(value, index, list) {
       var computed = iterator ? iterator.call(context, value, index, list) : value;
@@ -231,6 +237,7 @@
   // Return the minimum element (or element-based computation).
   _.min = function(obj, iterator, context) {
     if (!iterator && _.isArray(obj)) return Math.min.apply(Math, obj);
+    if (!iterator && _.isEmpty(obj)) return Infinity;
     var result = {computed : Infinity};
     each(obj, function(value, index, list) {
       var computed = iterator ? iterator.call(context, value, index, list) : value;
@@ -239,6 +246,21 @@
     return result.value;
   };
 
+  // Shuffle an array.
+  _.shuffle = function(obj) {
+    var shuffled = [], rand;
+    each(obj, function(value, index, list) {
+      if (index == 0) {
+        shuffled[0] = value;
+      } else {
+        rand = Math.floor(Math.random() * (index + 1));
+        shuffled[index] = shuffled[rand];
+        shuffled[rand] = value;
+      }
+    });
+    return shuffled;
+  };
+
   // Sort the object's values by a criterion produced by an iterator.
   _.sortBy = function(obj, iterator, context) {
     return _.pluck(_.map(obj, function(value, index, list) {
@@ -252,9 +274,11 @@
     }), 'value');
   };
 
-  // Groups the object's values by a criterion produced by an iterator
-  _.groupBy = function(obj, iterator) {
+  // Groups the object's values by a criterion. Pass either a string attribute
+  // to group by, or a function that returns the criterion.
+  _.groupBy = function(obj, val) {
     var result = {};
+    var iterator = _.isFunction(val) ? val : function(obj) { return obj[val]; };
     each(obj, function(value, index) {
       var key = iterator(value, index);
       (result[key] || (result[key] = [])).push(value);
@@ -298,6 +322,24 @@
     return (n != null) && !guard ? slice.call(array, 0, n) : array[0];
   };
 
+  // Returns everything but the last entry of the array. Especcialy useful on
+  // the arguments object. Passing **n** will return all the values in
+  // the array, excluding the last N. The **guard** check allows it to work with
+  // `_.map`.
+  _.initial = function(array, n, guard) {
+    return slice.call(array, 0, array.length - ((n == null) || guard ? 1 : n));
+  };
+
+  // Get the last element of an array. Passing **n** will return the last N
+  // values in the array. The **guard** check allows it to work with `_.map`.
+  _.last = function(array, n, guard) {
+    if ((n != null) && !guard) {
+      return slice.call(array, Math.max(array.length - n, 0));
+    } else {
+      return array[array.length - 1];
+    }
+  };
+
   // Returns everything but the first entry of the array. Aliased as `tail`.
   // Especially useful on the arguments object. Passing an **index** will return
   // the rest of the values in the array from that index onward. The **guard**
@@ -306,20 +348,15 @@
     return slice.call(array, (index == null) || guard ? 1 : index);
   };
 
-  // Get the last element of an array.
-  _.last = function(array) {
-    return array[array.length - 1];
-  };
-
   // Trim out all falsy values from an array.
   _.compact = function(array) {
     return _.filter(array, function(value){ return !!value; });
   };
 
   // Return a completely flattened version of an array.
-  _.flatten = function(array) {
+  _.flatten = function(array, shallow) {
     return _.reduce(array, function(memo, value) {
-      if (_.isArray(value)) return memo.concat(_.flatten(value));
+      if (_.isArray(value)) return memo.concat(shallow ? value : _.flatten(value));
       memo[memo.length] = value;
       return memo;
     }, []);
@@ -333,17 +370,23 @@
   // Produce a duplicate-free version of the array. If the array has already
   // been sorted, you have the option of using a faster algorithm.
   // Aliased as `unique`.
-  _.uniq = _.unique = function(array, isSorted) {
-    return _.reduce(array, function(memo, el, i) {
-      if (0 == i || (isSorted === true ? _.last(memo) != el : !_.include(memo, el))) memo[memo.length] = el;
+  _.uniq = _.unique = function(array, isSorted, iterator) {
+    var initial = iterator ? _.map(array, iterator) : array;
+    var result = [];
+    _.reduce(initial, function(memo, el, i) {
+      if (0 == i || (isSorted === true ? _.last(memo) != el : !_.include(memo, el))) {
+        memo[memo.length] = el;
+        result[result.length] = array[i];
+      }
       return memo;
     }, []);
+    return result;
   };
 
   // Produce an array that contains the union: each distinct element from all of
   // the passed-in arrays.
   _.union = function() {
-    return _.uniq(_.flatten(arguments));
+    return _.uniq(_.flatten(arguments, true));
   };
 
   // Produce an array that contains every item shared between all the
@@ -357,10 +400,11 @@
     });
   };
 
-  // Take the difference between one array and another.
+  // Take the difference between one array and a number of other arrays.
   // Only the elements present in just the first array will remain.
-  _.difference = function(array, other) {
-    return _.filter(array, function(value){ return !_.include(other, value); });
+  _.difference = function(array) {
+    var rest = _.flatten(slice.call(arguments, 1));
+    return _.filter(array, function(value){ return !_.include(rest, value); });
   };
 
   // Zip together multiple lists into a single array -- elements that share
@@ -387,17 +431,16 @@
       return array[i] === item ? i : -1;
     }
     if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item);
-    for (i = 0, l = array.length; i < l; i++) if (array[i] === item) return i;
+    for (i = 0, l = array.length; i < l; i++) if (i in array && array[i] === item) return i;
     return -1;
   };
 
-
   // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available.
   _.lastIndexOf = function(array, item) {
     if (array == null) return -1;
     if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) return array.lastIndexOf(item);
     var i = array.length;
-    while (i--) if (array[i] === item) return i;
+    while (i--) if (i in array && array[i] === item) return i;
     return -1;
   };
 
@@ -426,15 +469,25 @@
   // Function (ahem) Functions
   // ------------------
 
+  // Reusable constructor function for prototype setting.
+  var ctor = function(){};
+
   // Create a function bound to a given object (assigning `this`, and arguments,
   // optionally). Binding with arguments is also known as `curry`.
   // Delegates to **ECMAScript 5**'s native `Function.bind` if available.
   // We check for `func.bind` first, to fail fast when `func` is undefined.
-  _.bind = function(func, obj) {
+  _.bind = function bind(func, context) {
+    var bound, args;
     if (func.bind === nativeBind && nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
-    var args = slice.call(arguments, 2);
-    return function() {
-      return func.apply(obj, args.concat(slice.call(arguments)));
+    if (!_.isFunction(func)) throw new TypeError;
+    args = slice.call(arguments, 2);
+    return bound = function() {
+      if (!(this instanceof bound)) return func.apply(context, args.concat(slice.call(arguments)));
+      ctor.prototype = func.prototype;
+      var self = new ctor;
+      var result = func.apply(self, args.concat(slice.call(arguments)));
+      if (Object(result) === result) return result;
+      return self;
     };
   };
 
@@ -453,7 +506,7 @@
     hasher || (hasher = _.identity);
     return function() {
       var key = hasher.apply(this, arguments);
-      return hasOwnProperty.call(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
+      return _.has(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
     };
   };
 
@@ -470,31 +523,43 @@
     return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
   };
 
-  // Internal function used to implement `_.throttle` and `_.debounce`.
-  var limit = function(func, wait, debounce) {
-    var timeout;
-    return function() {
-      var context = this, args = arguments;
-      var throttler = function() {
-        timeout = null;
-        func.apply(context, args);
-      };
-      if (debounce) clearTimeout(timeout);
-      if (debounce || !timeout) timeout = setTimeout(throttler, wait);
-    };
-  };
-
   // Returns a function, that, when invoked, will only be triggered at most once
   // during a given window of time.
   _.throttle = function(func, wait) {
-    return limit(func, wait, false);
+    var context, args, timeout, throttling, more;
+    var whenDone = _.debounce(function(){ more = throttling = false; }, wait);
+    return function() {
+      context = this; args = arguments;
+      var later = function() {
+        timeout = null;
+        if (more) func.apply(context, args);
+        whenDone();
+      };
+      if (!timeout) timeout = setTimeout(later, wait);
+      if (throttling) {
+        more = true;
+      } else {
+        func.apply(context, args);
+      }
+      whenDone();
+      throttling = true;
+    };
   };
 
   // Returns a function, that, as long as it continues to be invoked, will not
   // be triggered. The function will be called after it stops being called for
   // N milliseconds.
   _.debounce = function(func, wait) {
-    return limit(func, wait, true);
+    var timeout;
+    return function() {
+      var context = this, args = arguments;
+      var later = function() {
+        timeout = null;
+        func.apply(context, args);
+      };
+      clearTimeout(timeout);
+      timeout = setTimeout(later, wait);
+    };
   };
 
   // Returns a function that will be executed at most one time, no matter how
@@ -513,7 +578,7 @@
   // conditionally execute the original function.
   _.wrap = function(func, wrapper) {
     return function() {
-      var args = [func].concat(slice.call(arguments));
+      var args = [func].concat(slice.call(arguments, 0));
       return wrapper.apply(this, args);
     };
   };
@@ -521,9 +586,9 @@
   // Returns a function that is the composition of a list of functions, each
   // consuming the return value of the function that follows.
   _.compose = function() {
-    var funcs = slice.call(arguments);
+    var funcs = arguments;
     return function() {
-      var args = slice.call(arguments);
+      var args = arguments;
       for (var i = funcs.length - 1; i >= 0; i--) {
         args = [funcs[i].apply(this, args)];
       }
@@ -533,12 +598,12 @@
 
   // Returns a function that will only be executed after being called N times.
   _.after = function(times, func) {
+    if (times <= 0) return func();
     return function() {
       if (--times < 1) { return func.apply(this, arguments); }
     };
   };
 
-
   // Object Functions
   // ----------------
 
@@ -547,7 +612,7 @@
   _.keys = nativeKeys || function(obj) {
     if (obj !== Object(obj)) throw new TypeError('Invalid object');
     var keys = [];
-    for (var key in obj) if (hasOwnProperty.call(obj, key)) keys[keys.length] = key;
+    for (var key in obj) if (_.has(obj, key)) keys[keys.length] = key;
     return keys;
   };
 
@@ -570,7 +635,7 @@
   _.extend = function(obj) {
     each(slice.call(arguments, 1), function(source) {
       for (var prop in source) {
-        if (source[prop] !== void 0) obj[prop] = source[prop];
+        obj[prop] = source[prop];
       }
     });
     return obj;
@@ -588,6 +653,7 @@
 
   // Create a (shallow-cloned) duplicate of an object.
   _.clone = function(obj) {
+    if (!_.isObject(obj)) return obj;
     return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
   };
 
@@ -599,50 +665,104 @@
     return obj;
   };
 
-  // Perform a deep comparison to check if two objects are equal.
-  _.isEqual = function(a, b) {
-    // Check object identity.
-    if (a === b) return true;
-    // Different types?
-    var atype = typeof(a), btype = typeof(b);
-    if (atype != btype) return false;
-    // Basic equality test (watch out for coercions).
-    if (a == b) return true;
-    // One is falsy and the other truthy.
-    if ((!a && b) || (a && !b)) return false;
+  // Internal recursive comparison function.
+  function eq(a, b, stack) {
+    // Identical objects are equal. `0 === -0`, but they aren't identical.
+    // See the Harmony `egal` proposal: http://wiki.ecmascript.org/doku.php?id=harmony:egal.
+    if (a === b) return a !== 0 || 1 / a == 1 / b;
+    // A strict comparison is necessary because `null == undefined`.
+    if (a == null || b == null) return a === b;
     // Unwrap any wrapped objects.
     if (a._chain) a = a._wrapped;
     if (b._chain) b = b._wrapped;
-    // One of them implements an isEqual()?
-    if (a.isEqual) return a.isEqual(b);
-    if (b.isEqual) return b.isEqual(a);
-    // Check dates' integer values.
-    if (_.isDate(a) && _.isDate(b)) return a.getTime() === b.getTime();
-    // Both are NaN?
-    if (_.isNaN(a) && _.isNaN(b)) return false;
-    // Compare regular expressions.
-    if (_.isRegExp(a) && _.isRegExp(b))
-      return a.source     === b.source &&
-             a.global     === b.global &&
-             a.ignoreCase === b.ignoreCase &&
-             a.multiline  === b.multiline;
-    // If a is not an object by this point, we can't handle it.
-    if (atype !== 'object') return false;
-    // Check for different array lengths before comparing contents.
-    if (a.length && (a.length !== b.length)) return false;
-    // Nothing else worked, deep compare the contents.
-    var aKeys = _.keys(a), bKeys = _.keys(b);
-    // Different object sizes?
-    if (aKeys.length != bKeys.length) return false;
-    // Recursive comparison of contents.
-    for (var key in a) if (!(key in b) || !_.isEqual(a[key], b[key])) return false;
-    return true;
+    // Invoke a custom `isEqual` method if one is provided.
+    if (a.isEqual && _.isFunction(a.isEqual)) return a.isEqual(b);
+    if (b.isEqual && _.isFunction(b.isEqual)) return b.isEqual(a);
+    // Compare `[[Class]]` names.
+    var className = toString.call(a);
+    if (className != toString.call(b)) return false;
+    switch (className) {
+      // Strings, numbers, dates, and booleans are compared by value.
+      case '[object String]':
+        // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is
+        // equivalent to `new String("5")`.
+        return a == String(b);
+      case '[object Number]':
+        // `NaN`s are equivalent, but non-reflexive. An `egal` comparison is performed for
+        // other numeric values.
+        return a != +a ? b != +b : (a == 0 ? 1 / a == 1 / b : a == +b);
+      case '[object Date]':
+      case '[object Boolean]':
+        // Coerce dates and booleans to numeric primitive values. Dates are compared by their
+        // millisecond representations. Note that invalid dates with millisecond representations
+        // of `NaN` are not equivalent.
+        return +a == +b;
+      // RegExps are compared by their source patterns and flags.
+      case '[object RegExp]':
+        return a.source == b.source &&
+               a.global == b.global &&
+               a.multiline == b.multiline &&
+               a.ignoreCase == b.ignoreCase;
+    }
+    if (typeof a != 'object' || typeof b != 'object') return false;
+    // Assume equality for cyclic structures. The algorithm for detecting cyclic
+    // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
+    var length = stack.length;
+    while (length--) {
+      // Linear search. Performance is inversely proportional to the number of
+      // unique nested structures.
+      if (stack[length] == a) return true;
+    }
+    // Add the first object to the stack of traversed objects.
+    stack.push(a);
+    var size = 0, result = true;
+    // Recursively compare objects and arrays.
+    if (className == '[object Array]') {
+      // Compare array lengths to determine if a deep comparison is necessary.
+      size = a.length;
+      result = size == b.length;
+      if (result) {
+        // Deep compare the contents, ignoring non-numeric properties.
+        while (size--) {
+          // Ensure commutative equality for sparse arrays.
+          if (!(result = size in a == size in b && eq(a[size], b[size], stack))) break;
+        }
+      }
+    } else {
+      // Objects with different constructors are not equivalent.
+      if ('constructor' in a != 'constructor' in b || a.constructor != b.constructor) return false;
+      // Deep compare objects.
+      for (var key in a) {
+        if (_.has(a, key)) {
+          // Count the expected number of properties.
+          size++;
+          // Deep compare each member.
+          if (!(result = _.has(b, key) && eq(a[key], b[key], stack))) break;
+        }
+      }
+      // Ensure that both objects contain the same number of properties.
+      if (result) {
+        for (key in b) {
+          if (_.has(b, key) && !(size--)) break;
+        }
+        result = !size;
+      }
+    }
+    // Remove the first object from the stack of traversed objects.
+    stack.pop();
+    return result;
+  }
+
+  // Perform a deep comparison to check if two objects are equal.
+  _.isEqual = function(a, b) {
+    return eq(a, b, []);
   };
 
-  // Is a given array or object empty?
+  // Is a given array, string, or object empty?
+  // An "empty" object has no enumerable own-properties.
   _.isEmpty = function(obj) {
     if (_.isArray(obj) || _.isString(obj)) return obj.length === 0;
-    for (var key in obj) if (hasOwnProperty.call(obj, key)) return false;
+    for (var key in obj) if (_.has(obj, key)) return false;
     return true;
   };
 
@@ -654,7 +774,7 @@
   // Is a given value an array?
   // Delegates to ECMA5's native Array.isArray
   _.isArray = nativeIsArray || function(obj) {
-    return toString.call(obj) === '[object Array]';
+    return toString.call(obj) == '[object Array]';
   };
 
   // Is a given variable an object?
@@ -664,43 +784,48 @@
 
   // Is a given variable an arguments object?
   _.isArguments = function(obj) {
-    return !!(obj && hasOwnProperty.call(obj, 'callee'));
+    return toString.call(obj) == '[object Arguments]';
   };
+  if (!_.isArguments(arguments)) {
+    _.isArguments = function(obj) {
+      return !!(obj && _.has(obj, 'callee'));
+    };
+  }
 
   // Is a given value a function?
   _.isFunction = function(obj) {
-    return !!(obj && obj.constructor && obj.call && obj.apply);
+    return toString.call(obj) == '[object Function]';
   };
 
   // Is a given value a string?
   _.isString = function(obj) {
-    return !!(obj === '' || (obj && obj.charCodeAt && obj.substr));
+    return toString.call(obj) == '[object String]';
   };
 
   // Is a given value a number?
   _.isNumber = function(obj) {
-    return !!(obj === 0 || (obj && obj.toExponential && obj.toFixed));
+    return toString.call(obj) == '[object Number]';
   };
 
-  // Is the given value `NaN`? `NaN` happens to be the only value in JavaScript
-  // that does not equal itself.
+  // Is the given value `NaN`?
   _.isNaN = function(obj) {
+    // `NaN` is the only value for which `===` is not reflexive.
     return obj !== obj;
   };
 
   // Is a given value a boolean?
   _.isBoolean = function(obj) {
-    return obj === true || obj === false;
+    return obj === true || obj === false || toString.call(obj) == '[object Boolean]';
   };
 
   // Is a given value a date?
   _.isDate = function(obj) {
-    return !!(obj && obj.getTimezoneOffset && obj.setUTCFullYear);
+    return toString.call(obj) == '[object Date]';
   };
 
   // Is the given value a regular expression?
   _.isRegExp = function(obj) {
-    return !!(obj && obj.test && obj.exec && (obj.ignoreCase || obj.ignoreCase === false));
+    return toString.call(obj) == '[object RegExp]';
   };
 
   // Is a given value equal to null?
@@ -713,6 +838,11 @@
     return obj === void 0;
   };
 
+  // Has own property?
+  _.has = function(obj, key) {
+    return hasOwnProperty.call(obj, key);
+  };
+
   // Utility Functions
   // -----------------
 
@@ -733,6 +863,11 @@
     for (var i = 0; i < n; i++) iterator.call(context, i);
   };
 
+  // Escape a string for HTML interpolation.
+  _.escape = function(string) {
+    return (''+string).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;').replace(/'/g, '&#x27;').replace(/\//g,'&#x2F;');
+  };
+
   // Add your own custom functions to the Underscore object, ensuring that
   // they're correctly added to the OOP wrapper as well.
   _.mixin = function(obj) {
@@ -753,7 +888,19 @@
   // following template settings to use alternative delimiters.
   _.templateSettings = {
     evaluate    : /<%([\s\S]+?)%>/g,
-    interpolate : /<%=([\s\S]+?)%>/g
+    interpolate : /<%=([\s\S]+?)%>/g,
+    escape      : /<%-([\s\S]+?)%>/g
+  };
+
+  // When customizing `templateSettings`, if you don't want to define an
+  // interpolation, evaluation or escaping regex, we need one that is
+  // guaranteed not to match.
+  var noMatch = /.^/;
+
+  // Within an interpolation, evaluation, or escaping, remove HTML escaping
+  // that had been previously added.
+  var unescape = function(code) {
+    return code.replace(/\\\\/g, '\\').replace(/\\'/g, "'");
   };
 
   // JavaScript micro-templating, similar to John Resig's implementation.
@@ -765,19 +912,29 @@
       'with(obj||{}){__p.push(\'' +
       str.replace(/\\/g, '\\\\')
          .replace(/'/g, "\\'")
-         .replace(c.interpolate, function(match, code) {
-           return "'," + code.replace(/\\'/g, "'") + ",'";
+         .replace(c.escape || noMatch, function(match, code) {
+           return "',_.escape(" + unescape(code) + "),'";
          })
-         .replace(c.evaluate || null, function(match, code) {
-           return "');" + code.replace(/\\'/g, "'")
-                              .replace(/[\r\n\t]/g, ' ') + "__p.push('";
+         .replace(c.interpolate || noMatch, function(match, code) {
+           return "'," + unescape(code) + ",'";
+         })
+         .replace(c.evaluate || noMatch, function(match, code) {
+           return "');" + unescape(code).replace(/[\r\n\t]/g, ' ') + ";__p.push('";
          })
          .replace(/\r/g, '\\r')
          .replace(/\n/g, '\\n')
          .replace(/\t/g, '\\t')
          + "');}return __p.join('');";
-    var func = new Function('obj', tmpl);
-    return data ? func(data) : func;
+    var func = new Function('obj', '_', tmpl);
+    if (data) return func(data, _);
+    return function(data) {
+      return func.call(this, data, _);
+    };
+  };
+
+  // Add a "chain" function, which will delegate to the wrapper.
+  _.chain = function(obj) {
+    return _(obj).chain();
   };
 
   // The OOP Wrapper
@@ -812,8 +969,11 @@
   each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
     var method = ArrayProto[name];
     wrapper.prototype[name] = function() {
-      method.apply(this._wrapped, arguments);
-      return result(this._wrapped, this._chain);
+      var wrapped = this._wrapped;
+      method.apply(wrapped, arguments);
+      var length = wrapped.length;
+      if ((name == 'shift' || name == 'splice') && length === 0) delete wrapped[0];
+      return result(wrapped, this._chain);
     };
   });
 
@@ -836,4 +996,4 @@
     return this._wrapped;
   };
 
-})();
+}).call(this);
diff --git a/app/server/underscore.js b/app/server/underscore.js
index 4f56013259..208d4cd890 100644
--- a/app/server/underscore.js
+++ b/app/server/underscore.js
@@ -1,5 +1,5 @@
-//     Underscore.js 1.1.7
-//     (c) 2011 Jeremy Ashkenas, DocumentCloud Inc.
+//     Underscore.js 1.3.1
+//     (c) 2009-2012 Jeremy Ashkenas, DocumentCloud Inc.
 //     Underscore is freely distributable under the MIT license.
 //     Portions of Underscore are inspired or borrowed from Prototype,
 //     Oliver Steele's Functional, and John Resig's Micro-Templating.
@@ -48,19 +48,21 @@
   // Create a safe reference to the Underscore object for use below.
   var _ = function(obj) { return new wrapper(obj); };
 
-  // Export the Underscore object for **CommonJS**, with backwards-compatibility
-  // for the old `require()` API. If we're not in CommonJS, add `_` to the
-  // global object.
-  if (typeof module !== 'undefined' && module.exports) {
-    module.exports = _;
-    _._ = _;
+  // Export the Underscore object for **Node.js**, with
+  // backwards-compatibility for the old `require()` API. If we're in
+  // the browser, add `_` as a global object via a string identifier,
+  // for Closure Compiler "advanced" mode.
+  if (typeof exports !== 'undefined') {
+    if (typeof module !== 'undefined' && module.exports) {
+      exports = module.exports = _;
+    }
+    exports._ = _;
   } else {
-    // Exported as a string, for Closure Compiler "advanced" mode.
     root['_'] = _;
   }
 
   // Current version.
-  _.VERSION = '1.1.7';
+  _.VERSION = '1.3.1';
 
   // Collection Functions
   // --------------------
@@ -78,7 +80,7 @@
       }
     } else {
       for (var key in obj) {
-        if (hasOwnProperty.call(obj, key)) {
+        if (_.has(obj, key)) {
           if (iterator.call(context, obj[key], key, obj) === breaker) return;
         }
       }
@@ -87,20 +89,21 @@
 
   // Return the results of applying the iterator to each element.
   // Delegates to **ECMAScript 5**'s native `map` if available.
-  _.map = function(obj, iterator, context) {
+  _.map = _.collect = function(obj, iterator, context) {
     var results = [];
     if (obj == null) return results;
     if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context);
     each(obj, function(value, index, list) {
       results[results.length] = iterator.call(context, value, index, list);
     });
+    if (obj.length === +obj.length) results.length = obj.length;
     return results;
   };
 
   // **Reduce** builds up a single result from a list of values, aka `inject`,
   // or `foldl`. Delegates to **ECMAScript 5**'s native `reduce` if available.
   _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) {
-    var initial = memo !== void 0;
+    var initial = arguments.length > 2;
     if (obj == null) obj = [];
     if (nativeReduce && obj.reduce === nativeReduce) {
       if (context) iterator = _.bind(iterator, context);
@@ -114,20 +117,22 @@
         memo = iterator.call(context, memo, value, index, list);
       }
     });
-    if (!initial) throw new TypeError("Reduce of empty array with no initial value");
+    if (!initial) throw new TypeError('Reduce of empty array with no initial value');
     return memo;
   };
 
   // The right-associative version of reduce, also known as `foldr`.
   // Delegates to **ECMAScript 5**'s native `reduceRight` if available.
   _.reduceRight = _.foldr = function(obj, iterator, memo, context) {
+    var initial = arguments.length > 2;
     if (obj == null) obj = [];
     if (nativeReduceRight && obj.reduceRight === nativeReduceRight) {
       if (context) iterator = _.bind(iterator, context);
-      return memo !== void 0 ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
+      return initial ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
     }
-    var reversed = (_.isArray(obj) ? obj.slice() : _.toArray(obj)).reverse();
-    return _.reduce(reversed, iterator, memo, context);
+    var reversed = _.toArray(obj).reverse();
+    if (context && !initial) iterator = _.bind(iterator, context);
+    return initial ? _.reduce(reversed, iterator, memo, context) : _.reduce(reversed, iterator);
   };
 
   // Return the first value which passes a truth test. Aliased as `detect`.
@@ -182,12 +187,12 @@
   // Delegates to **ECMAScript 5**'s native `some` if available.
   // Aliased as `any`.
   var any = _.some = _.any = function(obj, iterator, context) {
-    iterator = iterator || _.identity;
+    iterator || (iterator = _.identity);
     var result = false;
     if (obj == null) return result;
     if (nativeSome && obj.some === nativeSome) return obj.some(iterator, context);
     each(obj, function(value, index, list) {
-      if (result |= iterator.call(context, value, index, list)) return breaker;
+      if (result || (result = iterator.call(context, value, index, list))) return breaker;
     });
     return !!result;
   };
@@ -198,8 +203,8 @@
     var found = false;
     if (obj == null) return found;
     if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
-    any(obj, function(value) {
-      if (found = value === target) return true;
+    found = any(obj, function(value) {
+      return value === target;
     });
     return found;
   };
@@ -208,7 +213,7 @@
   _.invoke = function(obj, method) {
     var args = slice.call(arguments, 2);
     return _.map(obj, function(value) {
-      return (method.call ? method || value : value[method]).apply(value, args);
+      return (_.isFunction(method) ? method || value : value[method]).apply(value, args);
     });
   };
 
@@ -220,6 +225,7 @@
   // Return the maximum element or (element-based computation).
   _.max = function(obj, iterator, context) {
     if (!iterator && _.isArray(obj)) return Math.max.apply(Math, obj);
+    if (!iterator && _.isEmpty(obj)) return -Infinity;
     var result = {computed : -Infinity};
     each(obj, function(value, index, list) {
       var computed = iterator ? iterator.call(context, value, index, list) : value;
@@ -231,6 +237,7 @@
   // Return the minimum element (or element-based computation).
   _.min = function(obj, iterator, context) {
     if (!iterator && _.isArray(obj)) return Math.min.apply(Math, obj);
+    if (!iterator && _.isEmpty(obj)) return Infinity;
     var result = {computed : Infinity};
     each(obj, function(value, index, list) {
       var computed = iterator ? iterator.call(context, value, index, list) : value;
@@ -239,6 +246,21 @@
     return result.value;
   };
 
+  // Shuffle an array.
+  _.shuffle = function(obj) {
+    var shuffled = [], rand;
+    each(obj, function(value, index, list) {
+      if (index == 0) {
+        shuffled[0] = value;
+      } else {
+        rand = Math.floor(Math.random() * (index + 1));
+        shuffled[index] = shuffled[rand];
+        shuffled[rand] = value;
+      }
+    });
+    return shuffled;
+  };
+
   // Sort the object's values by a criterion produced by an iterator.
   _.sortBy = function(obj, iterator, context) {
     return _.pluck(_.map(obj, function(value, index, list) {
@@ -252,9 +274,11 @@
     }), 'value');
   };
 
-  // Groups the object's values by a criterion produced by an iterator
-  _.groupBy = function(obj, iterator) {
+  // Groups the object's values by a criterion. Pass either a string attribute
+  // to group by, or a function that returns the criterion.
+  _.groupBy = function(obj, val) {
     var result = {};
+    var iterator = _.isFunction(val) ? val : function(obj) { return obj[val]; };
     each(obj, function(value, index) {
       var key = iterator(value, index);
       (result[key] || (result[key] = [])).push(value);
@@ -298,6 +322,24 @@
     return (n != null) && !guard ? slice.call(array, 0, n) : array[0];
   };
 
+  // Returns everything but the last entry of the array. Especcialy useful on
+  // the arguments object. Passing **n** will return all the values in
+  // the array, excluding the last N. The **guard** check allows it to work with
+  // `_.map`.
+  _.initial = function(array, n, guard) {
+    return slice.call(array, 0, array.length - ((n == null) || guard ? 1 : n));
+  };
+
+  // Get the last element of an array. Passing **n** will return the last N
+  // values in the array. The **guard** check allows it to work with `_.map`.
+  _.last = function(array, n, guard) {
+    if ((n != null) && !guard) {
+      return slice.call(array, Math.max(array.length - n, 0));
+    } else {
+      return array[array.length - 1];
+    }
+  };
+
   // Returns everything but the first entry of the array. Aliased as `tail`.
   // Especially useful on the arguments object. Passing an **index** will return
   // the rest of the values in the array from that index onward. The **guard**
@@ -306,20 +348,15 @@
     return slice.call(array, (index == null) || guard ? 1 : index);
   };
 
-  // Get the last element of an array.
-  _.last = function(array) {
-    return array[array.length - 1];
-  };
-
   // Trim out all falsy values from an array.
   _.compact = function(array) {
     return _.filter(array, function(value){ return !!value; });
   };
 
   // Return a completely flattened version of an array.
-  _.flatten = function(array) {
+  _.flatten = function(array, shallow) {
     return _.reduce(array, function(memo, value) {
-      if (_.isArray(value)) return memo.concat(_.flatten(value));
+      if (_.isArray(value)) return memo.concat(shallow ? value : _.flatten(value));
       memo[memo.length] = value;
       return memo;
     }, []);
@@ -333,17 +370,23 @@
   // Produce a duplicate-free version of the array. If the array has already
   // been sorted, you have the option of using a faster algorithm.
   // Aliased as `unique`.
-  _.uniq = _.unique = function(array, isSorted) {
-    return _.reduce(array, function(memo, el, i) {
-      if (0 == i || (isSorted === true ? _.last(memo) != el : !_.include(memo, el))) memo[memo.length] = el;
+  _.uniq = _.unique = function(array, isSorted, iterator) {
+    var initial = iterator ? _.map(array, iterator) : array;
+    var result = [];
+    _.reduce(initial, function(memo, el, i) {
+      if (0 == i || (isSorted === true ? _.last(memo) != el : !_.include(memo, el))) {
+        memo[memo.length] = el;
+        result[result.length] = array[i];
+      }
       return memo;
     }, []);
+    return result;
   };
 
   // Produce an array that contains the union: each distinct element from all of
   // the passed-in arrays.
   _.union = function() {
-    return _.uniq(_.flatten(arguments));
+    return _.uniq(_.flatten(arguments, true));
   };
 
   // Produce an array that contains every item shared between all the
@@ -357,10 +400,11 @@
     });
   };
 
-  // Take the difference between one array and another.
+  // Take the difference between one array and a number of other arrays.
   // Only the elements present in just the first array will remain.
-  _.difference = function(array, other) {
-    return _.filter(array, function(value){ return !_.include(other, value); });
+  _.difference = function(array) {
+    var rest = _.flatten(slice.call(arguments, 1));
+    return _.filter(array, function(value){ return !_.include(rest, value); });
   };
 
   // Zip together multiple lists into a single array -- elements that share
@@ -387,17 +431,16 @@
       return array[i] === item ? i : -1;
     }
     if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item);
-    for (i = 0, l = array.length; i < l; i++) if (array[i] === item) return i;
+    for (i = 0, l = array.length; i < l; i++) if (i in array && array[i] === item) return i;
     return -1;
   };
 
-
   // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available.
   _.lastIndexOf = function(array, item) {
     if (array == null) return -1;
     if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) return array.lastIndexOf(item);
     var i = array.length;
-    while (i--) if (array[i] === item) return i;
+    while (i--) if (i in array && array[i] === item) return i;
     return -1;
   };
 
@@ -426,15 +469,25 @@
   // Function (ahem) Functions
   // ------------------
 
+  // Reusable constructor function for prototype setting.
+  var ctor = function(){};
+
   // Create a function bound to a given object (assigning `this`, and arguments,
   // optionally). Binding with arguments is also known as `curry`.
   // Delegates to **ECMAScript 5**'s native `Function.bind` if available.
   // We check for `func.bind` first, to fail fast when `func` is undefined.
-  _.bind = function(func, obj) {
+  _.bind = function bind(func, context) {
+    var bound, args;
     if (func.bind === nativeBind && nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
-    var args = slice.call(arguments, 2);
-    return function() {
-      return func.apply(obj, args.concat(slice.call(arguments)));
+    if (!_.isFunction(func)) throw new TypeError;
+    args = slice.call(arguments, 2);
+    return bound = function() {
+      if (!(this instanceof bound)) return func.apply(context, args.concat(slice.call(arguments)));
+      ctor.prototype = func.prototype;
+      var self = new ctor;
+      var result = func.apply(self, args.concat(slice.call(arguments)));
+      if (Object(result) === result) return result;
+      return self;
     };
   };
 
@@ -453,7 +506,7 @@
     hasher || (hasher = _.identity);
     return function() {
       var key = hasher.apply(this, arguments);
-      return hasOwnProperty.call(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
+      return _.has(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
     };
   };
 
@@ -470,31 +523,43 @@
     return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
   };
 
-  // Internal function used to implement `_.throttle` and `_.debounce`.
-  var limit = function(func, wait, debounce) {
-    var timeout;
-    return function() {
-      var context = this, args = arguments;
-      var throttler = function() {
-        timeout = null;
-        func.apply(context, args);
-      };
-      if (debounce) clearTimeout(timeout);
-      if (debounce || !timeout) timeout = setTimeout(throttler, wait);
-    };
-  };
-
   // Returns a function, that, when invoked, will only be triggered at most once
   // during a given window of time.
   _.throttle = function(func, wait) {
-    return limit(func, wait, false);
+    var context, args, timeout, throttling, more;
+    var whenDone = _.debounce(function(){ more = throttling = false; }, wait);
+    return function() {
+      context = this; args = arguments;
+      var later = function() {
+        timeout = null;
+        if (more) func.apply(context, args);
+        whenDone();
+      };
+      if (!timeout) timeout = setTimeout(later, wait);
+      if (throttling) {
+        more = true;
+      } else {
+        func.apply(context, args);
+      }
+      whenDone();
+      throttling = true;
+    };
   };
 
   // Returns a function, that, as long as it continues to be invoked, will not
   // be triggered. The function will be called after it stops being called for
   // N milliseconds.
   _.debounce = function(func, wait) {
-    return limit(func, wait, true);
+    var timeout;
+    return function() {
+      var context = this, args = arguments;
+      var later = function() {
+        timeout = null;
+        func.apply(context, args);
+      };
+      clearTimeout(timeout);
+      timeout = setTimeout(later, wait);
+    };
   };
 
   // Returns a function that will be executed at most one time, no matter how
@@ -513,7 +578,7 @@
   // conditionally execute the original function.
   _.wrap = function(func, wrapper) {
     return function() {
-      var args = [func].concat(slice.call(arguments));
+      var args = [func].concat(slice.call(arguments, 0));
       return wrapper.apply(this, args);
     };
   };
@@ -521,9 +586,9 @@
   // Returns a function that is the composition of a list of functions, each
   // consuming the return value of the function that follows.
   _.compose = function() {
-    var funcs = slice.call(arguments);
+    var funcs = arguments;
     return function() {
-      var args = slice.call(arguments);
+      var args = arguments;
       for (var i = funcs.length - 1; i >= 0; i--) {
         args = [funcs[i].apply(this, args)];
       }
@@ -533,12 +598,12 @@
 
   // Returns a function that will only be executed after being called N times.
   _.after = function(times, func) {
+    if (times <= 0) return func();
     return function() {
       if (--times < 1) { return func.apply(this, arguments); }
     };
   };
 
-
   // Object Functions
   // ----------------
 
@@ -547,7 +612,7 @@
   _.keys = nativeKeys || function(obj) {
     if (obj !== Object(obj)) throw new TypeError('Invalid object');
     var keys = [];
-    for (var key in obj) if (hasOwnProperty.call(obj, key)) keys[keys.length] = key;
+    for (var key in obj) if (_.has(obj, key)) keys[keys.length] = key;
     return keys;
   };
 
@@ -570,7 +635,7 @@
   _.extend = function(obj) {
     each(slice.call(arguments, 1), function(source) {
       for (var prop in source) {
-        if (source[prop] !== void 0) obj[prop] = source[prop];
+        obj[prop] = source[prop];
       }
     });
     return obj;
@@ -588,6 +653,7 @@
 
   // Create a (shallow-cloned) duplicate of an object.
   _.clone = function(obj) {
+    if (!_.isObject(obj)) return obj;
     return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
   };
 
@@ -599,50 +665,104 @@
     return obj;
   };
 
-  // Perform a deep comparison to check if two objects are equal.
-  _.isEqual = function(a, b) {
-    // Check object identity.
-    if (a === b) return true;
-    // Different types?
-    var atype = typeof(a), btype = typeof(b);
-    if (atype != btype) return false;
-    // Basic equality test (watch out for coercions).
-    if (a == b) return true;
-    // One is falsy and the other truthy.
-    if ((!a && b) || (a && !b)) return false;
+  // Internal recursive comparison function.
+  function eq(a, b, stack) {
+    // Identical objects are equal. `0 === -0`, but they aren't identical.
+    // See the Harmony `egal` proposal: http://wiki.ecmascript.org/doku.php?id=harmony:egal.
+    if (a === b) return a !== 0 || 1 / a == 1 / b;
+    // A strict comparison is necessary because `null == undefined`.
+    if (a == null || b == null) return a === b;
     // Unwrap any wrapped objects.
     if (a._chain) a = a._wrapped;
     if (b._chain) b = b._wrapped;
-    // One of them implements an isEqual()?
-    if (a.isEqual) return a.isEqual(b);
-    if (b.isEqual) return b.isEqual(a);
-    // Check dates' integer values.
-    if (_.isDate(a) && _.isDate(b)) return a.getTime() === b.getTime();
-    // Both are NaN?
-    if (_.isNaN(a) && _.isNaN(b)) return false;
-    // Compare regular expressions.
-    if (_.isRegExp(a) && _.isRegExp(b))
-      return a.source     === b.source &&
-             a.global     === b.global &&
-             a.ignoreCase === b.ignoreCase &&
-             a.multiline  === b.multiline;
-    // If a is not an object by this point, we can't handle it.
-    if (atype !== 'object') return false;
-    // Check for different array lengths before comparing contents.
-    if (a.length && (a.length !== b.length)) return false;
-    // Nothing else worked, deep compare the contents.
-    var aKeys = _.keys(a), bKeys = _.keys(b);
-    // Different object sizes?
-    if (aKeys.length != bKeys.length) return false;
-    // Recursive comparison of contents.
-    for (var key in a) if (!(key in b) || !_.isEqual(a[key], b[key])) return false;
-    return true;
+    // Invoke a custom `isEqual` method if one is provided.
+    if (a.isEqual && _.isFunction(a.isEqual)) return a.isEqual(b);
+    if (b.isEqual && _.isFunction(b.isEqual)) return b.isEqual(a);
+    // Compare `[[Class]]` names.
+    var className = toString.call(a);
+    if (className != toString.call(b)) return false;
+    switch (className) {
+      // Strings, numbers, dates, and booleans are compared by value.
+      case '[object String]':
+        // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is
+        // equivalent to `new String("5")`.
+        return a == String(b);
+      case '[object Number]':
+        // `NaN`s are equivalent, but non-reflexive. An `egal` comparison is performed for
+        // other numeric values.
+        return a != +a ? b != +b : (a == 0 ? 1 / a == 1 / b : a == +b);
+      case '[object Date]':
+      case '[object Boolean]':
+        // Coerce dates and booleans to numeric primitive values. Dates are compared by their
+        // millisecond representations. Note that invalid dates with millisecond representations
+        // of `NaN` are not equivalent.
+        return +a == +b;
+      // RegExps are compared by their source patterns and flags.
+      case '[object RegExp]':
+        return a.source == b.source &&
+               a.global == b.global &&
+               a.multiline == b.multiline &&
+               a.ignoreCase == b.ignoreCase;
+    }
+    if (typeof a != 'object' || typeof b != 'object') return false;
+    // Assume equality for cyclic structures. The algorithm for detecting cyclic
+    // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
+    var length = stack.length;
+    while (length--) {
+      // Linear search. Performance is inversely proportional to the number of
+      // unique nested structures.
+      if (stack[length] == a) return true;
+    }
+    // Add the first object to the stack of traversed objects.
+    stack.push(a);
+    var size = 0, result = true;
+    // Recursively compare objects and arrays.
+    if (className == '[object Array]') {
+      // Compare array lengths to determine if a deep comparison is necessary.
+      size = a.length;
+      result = size == b.length;
+      if (result) {
+        // Deep compare the contents, ignoring non-numeric properties.
+        while (size--) {
+          // Ensure commutative equality for sparse arrays.
+          if (!(result = size in a == size in b && eq(a[size], b[size], stack))) break;
+        }
+      }
+    } else {
+      // Objects with different constructors are not equivalent.
+      if ('constructor' in a != 'constructor' in b || a.constructor != b.constructor) return false;
+      // Deep compare objects.
+      for (var key in a) {
+        if (_.has(a, key)) {
+          // Count the expected number of properties.
+          size++;
+          // Deep compare each member.
+          if (!(result = _.has(b, key) && eq(a[key], b[key], stack))) break;
+        }
+      }
+      // Ensure that both objects contain the same number of properties.
+      if (result) {
+        for (key in b) {
+          if (_.has(b, key) && !(size--)) break;
+        }
+        result = !size;
+      }
+    }
+    // Remove the first object from the stack of traversed objects.
+    stack.pop();
+    return result;
+  }
+
+  // Perform a deep comparison to check if two objects are equal.
+  _.isEqual = function(a, b) {
+    return eq(a, b, []);
   };
 
-  // Is a given array or object empty?
+  // Is a given array, string, or object empty?
+  // An "empty" object has no enumerable own-properties.
   _.isEmpty = function(obj) {
     if (_.isArray(obj) || _.isString(obj)) return obj.length === 0;
-    for (var key in obj) if (hasOwnProperty.call(obj, key)) return false;
+    for (var key in obj) if (_.has(obj, key)) return false;
     return true;
   };
 
@@ -654,7 +774,7 @@
   // Is a given value an array?
   // Delegates to ECMA5's native Array.isArray
   _.isArray = nativeIsArray || function(obj) {
-    return toString.call(obj) === '[object Array]';
+    return toString.call(obj) == '[object Array]';
   };
 
   // Is a given variable an object?
@@ -664,43 +784,48 @@
 
   // Is a given variable an arguments object?
   _.isArguments = function(obj) {
-    return !!(obj && hasOwnProperty.call(obj, 'callee'));
+    return toString.call(obj) == '[object Arguments]';
   };
+  if (!_.isArguments(arguments)) {
+    _.isArguments = function(obj) {
+      return !!(obj && _.has(obj, 'callee'));
+    };
+  }
 
   // Is a given value a function?
   _.isFunction = function(obj) {
-    return !!(obj && obj.constructor && obj.call && obj.apply);
+    return toString.call(obj) == '[object Function]';
   };
 
   // Is a given value a string?
   _.isString = function(obj) {
-    return !!(obj === '' || (obj && obj.charCodeAt && obj.substr));
+    return toString.call(obj) == '[object String]';
   };
 
   // Is a given value a number?
   _.isNumber = function(obj) {
-    return !!(obj === 0 || (obj && obj.toExponential && obj.toFixed));
+    return toString.call(obj) == '[object Number]';
   };
 
-  // Is the given value `NaN`? `NaN` happens to be the only value in JavaScript
-  // that does not equal itself.
+  // Is the given value `NaN`?
   _.isNaN = function(obj) {
+    // `NaN` is the only value for which `===` is not reflexive.
     return obj !== obj;
   };
 
   // Is a given value a boolean?
   _.isBoolean = function(obj) {
-    return obj === true || obj === false;
+    return obj === true || obj === false || toString.call(obj) == '[object Boolean]';
   };
 
   // Is a given value a date?
   _.isDate = function(obj) {
-    return !!(obj && obj.getTimezoneOffset && obj.setUTCFullYear);
+    return toString.call(obj) == '[object Date]';
   };
 
   // Is the given value a regular expression?
   _.isRegExp = function(obj) {
-    return !!(obj && obj.test && obj.exec && (obj.ignoreCase || obj.ignoreCase === false));
+    return toString.call(obj) == '[object RegExp]';
   };
 
   // Is a given value equal to null?
@@ -713,6 +838,11 @@
     return obj === void 0;
   };
 
+  // Has own property?
+  _.has = function(obj, key) {
+    return hasOwnProperty.call(obj, key);
+  };
+
   // Utility Functions
   // -----------------
 
@@ -733,6 +863,11 @@
     for (var i = 0; i < n; i++) iterator.call(context, i);
   };
 
+  // Escape a string for HTML interpolation.
+  _.escape = function(string) {
+    return (''+string).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;').replace(/'/g, '&#x27;').replace(/\//g,'&#x2F;');
+  };
+
   // Add your own custom functions to the Underscore object, ensuring that
   // they're correctly added to the OOP wrapper as well.
   _.mixin = function(obj) {
@@ -753,7 +888,19 @@
   // following template settings to use alternative delimiters.
   _.templateSettings = {
     evaluate    : /<%([\s\S]+?)%>/g,
-    interpolate : /<%=([\s\S]+?)%>/g
+    interpolate : /<%=([\s\S]+?)%>/g,
+    escape      : /<%-([\s\S]+?)%>/g
+  };
+
+  // When customizing `templateSettings`, if you don't want to define an
+  // interpolation, evaluation or escaping regex, we need one that is
+  // guaranteed not to match.
+  var noMatch = /.^/;
+
+  // Within an interpolation, evaluation, or escaping, remove HTML escaping
+  // that had been previously added.
+  var unescape = function(code) {
+    return code.replace(/\\\\/g, '\\').replace(/\\'/g, "'");
   };
 
   // JavaScript micro-templating, similar to John Resig's implementation.
@@ -765,19 +912,29 @@
       'with(obj||{}){__p.push(\'' +
       str.replace(/\\/g, '\\\\')
          .replace(/'/g, "\\'")
-         .replace(c.interpolate, function(match, code) {
-           return "'," + code.replace(/\\'/g, "'") + ",'";
+         .replace(c.escape || noMatch, function(match, code) {
+           return "',_.escape(" + unescape(code) + "),'";
          })
-         .replace(c.evaluate || null, function(match, code) {
-           return "');" + code.replace(/\\'/g, "'")
-                              .replace(/[\r\n\t]/g, ' ') + "__p.push('";
+         .replace(c.interpolate || noMatch, function(match, code) {
+           return "'," + unescape(code) + ",'";
+         })
+         .replace(c.evaluate || noMatch, function(match, code) {
+           return "');" + unescape(code).replace(/[\r\n\t]/g, ' ') + ";__p.push('";
          })
          .replace(/\r/g, '\\r')
          .replace(/\n/g, '\\n')
          .replace(/\t/g, '\\t')
          + "');}return __p.join('');";
-    var func = new Function('obj', tmpl);
-    return data ? func(data) : func;
+    var func = new Function('obj', '_', tmpl);
+    if (data) return func(data, _);
+    return function(data) {
+      return func.call(this, data, _);
+    };
+  };
+
+  // Add a "chain" function, which will delegate to the wrapper.
+  _.chain = function(obj) {
+    return _(obj).chain();
   };
 
   // The OOP Wrapper
@@ -812,8 +969,11 @@
   each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
     var method = ArrayProto[name];
     wrapper.prototype[name] = function() {
-      method.apply(this._wrapped, arguments);
-      return result(this._wrapped, this._chain);
+      var wrapped = this._wrapped;
+      method.apply(wrapped, arguments);
+      var length = wrapped.length;
+      if ((name == 'shift' || name == 'splice') && length === 0) delete wrapped[0];
+      return result(wrapped, this._chain);
     };
   });
 
@@ -836,4 +996,4 @@
     return this._wrapped;
   };
 
-})();
+}).call(this);
diff --git a/packages/livedata/package.js b/packages/livedata/package.js
index 8587989b2b..d623525c7b 100644
--- a/packages/livedata/package.js
+++ b/packages/livedata/package.js
@@ -4,7 +4,7 @@ Package.describe({
 });
 
 Package.on_use(function (api) {
-  api.use('stream', 'uuid');
+  api.use(['stream', 'uuid']);
   api.use(['json', 'underscore'], 'server');
   api.use(['json', 'underscore', 'deps', 'minimongo', 'logging'], 'client');
 
diff --git a/packages/underscore/underscore.js b/packages/underscore/underscore.js
index 4f56013259..208d4cd890 100644
--- a/packages/underscore/underscore.js
+++ b/packages/underscore/underscore.js
@@ -1,5 +1,5 @@
-//     Underscore.js 1.1.7
-//     (c) 2011 Jeremy Ashkenas, DocumentCloud Inc.
+//     Underscore.js 1.3.1
+//     (c) 2009-2012 Jeremy Ashkenas, DocumentCloud Inc.
 //     Underscore is freely distributable under the MIT license.
 //     Portions of Underscore are inspired or borrowed from Prototype,
 //     Oliver Steele's Functional, and John Resig's Micro-Templating.
@@ -48,19 +48,21 @@
   // Create a safe reference to the Underscore object for use below.
   var _ = function(obj) { return new wrapper(obj); };
 
-  // Export the Underscore object for **CommonJS**, with backwards-compatibility
-  // for the old `require()` API. If we're not in CommonJS, add `_` to the
-  // global object.
-  if (typeof module !== 'undefined' && module.exports) {
-    module.exports = _;
-    _._ = _;
+  // Export the Underscore object for **Node.js**, with
+  // backwards-compatibility for the old `require()` API. If we're in
+  // the browser, add `_` as a global object via a string identifier,
+  // for Closure Compiler "advanced" mode.
+  if (typeof exports !== 'undefined') {
+    if (typeof module !== 'undefined' && module.exports) {
+      exports = module.exports = _;
+    }
+    exports._ = _;
   } else {
-    // Exported as a string, for Closure Compiler "advanced" mode.
     root['_'] = _;
   }
 
   // Current version.
-  _.VERSION = '1.1.7';
+  _.VERSION = '1.3.1';
 
   // Collection Functions
   // --------------------
@@ -78,7 +80,7 @@
       }
     } else {
       for (var key in obj) {
-        if (hasOwnProperty.call(obj, key)) {
+        if (_.has(obj, key)) {
           if (iterator.call(context, obj[key], key, obj) === breaker) return;
         }
       }
@@ -87,20 +89,21 @@
 
   // Return the results of applying the iterator to each element.
   // Delegates to **ECMAScript 5**'s native `map` if available.
-  _.map = function(obj, iterator, context) {
+  _.map = _.collect = function(obj, iterator, context) {
     var results = [];
     if (obj == null) return results;
     if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context);
     each(obj, function(value, index, list) {
       results[results.length] = iterator.call(context, value, index, list);
     });
+    if (obj.length === +obj.length) results.length = obj.length;
     return results;
   };
 
   // **Reduce** builds up a single result from a list of values, aka `inject`,
   // or `foldl`. Delegates to **ECMAScript 5**'s native `reduce` if available.
   _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) {
-    var initial = memo !== void 0;
+    var initial = arguments.length > 2;
     if (obj == null) obj = [];
     if (nativeReduce && obj.reduce === nativeReduce) {
       if (context) iterator = _.bind(iterator, context);
@@ -114,20 +117,22 @@
         memo = iterator.call(context, memo, value, index, list);
       }
     });
-    if (!initial) throw new TypeError("Reduce of empty array with no initial value");
+    if (!initial) throw new TypeError('Reduce of empty array with no initial value');
     return memo;
   };
 
   // The right-associative version of reduce, also known as `foldr`.
   // Delegates to **ECMAScript 5**'s native `reduceRight` if available.
   _.reduceRight = _.foldr = function(obj, iterator, memo, context) {
+    var initial = arguments.length > 2;
     if (obj == null) obj = [];
     if (nativeReduceRight && obj.reduceRight === nativeReduceRight) {
       if (context) iterator = _.bind(iterator, context);
-      return memo !== void 0 ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
+      return initial ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
     }
-    var reversed = (_.isArray(obj) ? obj.slice() : _.toArray(obj)).reverse();
-    return _.reduce(reversed, iterator, memo, context);
+    var reversed = _.toArray(obj).reverse();
+    if (context && !initial) iterator = _.bind(iterator, context);
+    return initial ? _.reduce(reversed, iterator, memo, context) : _.reduce(reversed, iterator);
   };
 
   // Return the first value which passes a truth test. Aliased as `detect`.
@@ -182,12 +187,12 @@
   // Delegates to **ECMAScript 5**'s native `some` if available.
   // Aliased as `any`.
   var any = _.some = _.any = function(obj, iterator, context) {
-    iterator = iterator || _.identity;
+    iterator || (iterator = _.identity);
     var result = false;
     if (obj == null) return result;
     if (nativeSome && obj.some === nativeSome) return obj.some(iterator, context);
     each(obj, function(value, index, list) {
-      if (result |= iterator.call(context, value, index, list)) return breaker;
+      if (result || (result = iterator.call(context, value, index, list))) return breaker;
     });
     return !!result;
   };
@@ -198,8 +203,8 @@
     var found = false;
     if (obj == null) return found;
     if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
-    any(obj, function(value) {
-      if (found = value === target) return true;
+    found = any(obj, function(value) {
+      return value === target;
     });
     return found;
   };
@@ -208,7 +213,7 @@
   _.invoke = function(obj, method) {
     var args = slice.call(arguments, 2);
     return _.map(obj, function(value) {
-      return (method.call ? method || value : value[method]).apply(value, args);
+      return (_.isFunction(method) ? method || value : value[method]).apply(value, args);
     });
   };
 
@@ -220,6 +225,7 @@
   // Return the maximum element or (element-based computation).
   _.max = function(obj, iterator, context) {
     if (!iterator && _.isArray(obj)) return Math.max.apply(Math, obj);
+    if (!iterator && _.isEmpty(obj)) return -Infinity;
     var result = {computed : -Infinity};
     each(obj, function(value, index, list) {
       var computed = iterator ? iterator.call(context, value, index, list) : value;
@@ -231,6 +237,7 @@
   // Return the minimum element (or element-based computation).
   _.min = function(obj, iterator, context) {
     if (!iterator && _.isArray(obj)) return Math.min.apply(Math, obj);
+    if (!iterator && _.isEmpty(obj)) return Infinity;
     var result = {computed : Infinity};
     each(obj, function(value, index, list) {
       var computed = iterator ? iterator.call(context, value, index, list) : value;
@@ -239,6 +246,21 @@
     return result.value;
   };
 
+  // Shuffle an array.
+  _.shuffle = function(obj) {
+    var shuffled = [], rand;
+    each(obj, function(value, index, list) {
+      if (index == 0) {
+        shuffled[0] = value;
+      } else {
+        rand = Math.floor(Math.random() * (index + 1));
+        shuffled[index] = shuffled[rand];
+        shuffled[rand] = value;
+      }
+    });
+    return shuffled;
+  };
+
   // Sort the object's values by a criterion produced by an iterator.
   _.sortBy = function(obj, iterator, context) {
     return _.pluck(_.map(obj, function(value, index, list) {
@@ -252,9 +274,11 @@
     }), 'value');
   };
 
-  // Groups the object's values by a criterion produced by an iterator
-  _.groupBy = function(obj, iterator) {
+  // Groups the object's values by a criterion. Pass either a string attribute
+  // to group by, or a function that returns the criterion.
+  _.groupBy = function(obj, val) {
     var result = {};
+    var iterator = _.isFunction(val) ? val : function(obj) { return obj[val]; };
     each(obj, function(value, index) {
       var key = iterator(value, index);
       (result[key] || (result[key] = [])).push(value);
@@ -298,6 +322,24 @@
     return (n != null) && !guard ? slice.call(array, 0, n) : array[0];
   };
 
+  // Returns everything but the last entry of the array. Especcialy useful on
+  // the arguments object. Passing **n** will return all the values in
+  // the array, excluding the last N. The **guard** check allows it to work with
+  // `_.map`.
+  _.initial = function(array, n, guard) {
+    return slice.call(array, 0, array.length - ((n == null) || guard ? 1 : n));
+  };
+
+  // Get the last element of an array. Passing **n** will return the last N
+  // values in the array. The **guard** check allows it to work with `_.map`.
+  _.last = function(array, n, guard) {
+    if ((n != null) && !guard) {
+      return slice.call(array, Math.max(array.length - n, 0));
+    } else {
+      return array[array.length - 1];
+    }
+  };
+
   // Returns everything but the first entry of the array. Aliased as `tail`.
   // Especially useful on the arguments object. Passing an **index** will return
   // the rest of the values in the array from that index onward. The **guard**
@@ -306,20 +348,15 @@
     return slice.call(array, (index == null) || guard ? 1 : index);
   };
 
-  // Get the last element of an array.
-  _.last = function(array) {
-    return array[array.length - 1];
-  };
-
   // Trim out all falsy values from an array.
   _.compact = function(array) {
     return _.filter(array, function(value){ return !!value; });
   };
 
   // Return a completely flattened version of an array.
-  _.flatten = function(array) {
+  _.flatten = function(array, shallow) {
     return _.reduce(array, function(memo, value) {
-      if (_.isArray(value)) return memo.concat(_.flatten(value));
+      if (_.isArray(value)) return memo.concat(shallow ? value : _.flatten(value));
       memo[memo.length] = value;
       return memo;
     }, []);
@@ -333,17 +370,23 @@
   // Produce a duplicate-free version of the array. If the array has already
   // been sorted, you have the option of using a faster algorithm.
   // Aliased as `unique`.
-  _.uniq = _.unique = function(array, isSorted) {
-    return _.reduce(array, function(memo, el, i) {
-      if (0 == i || (isSorted === true ? _.last(memo) != el : !_.include(memo, el))) memo[memo.length] = el;
+  _.uniq = _.unique = function(array, isSorted, iterator) {
+    var initial = iterator ? _.map(array, iterator) : array;
+    var result = [];
+    _.reduce(initial, function(memo, el, i) {
+      if (0 == i || (isSorted === true ? _.last(memo) != el : !_.include(memo, el))) {
+        memo[memo.length] = el;
+        result[result.length] = array[i];
+      }
       return memo;
     }, []);
+    return result;
   };
 
   // Produce an array that contains the union: each distinct element from all of
   // the passed-in arrays.
   _.union = function() {
-    return _.uniq(_.flatten(arguments));
+    return _.uniq(_.flatten(arguments, true));
   };
 
   // Produce an array that contains every item shared between all the
@@ -357,10 +400,11 @@
     });
   };
 
-  // Take the difference between one array and another.
+  // Take the difference between one array and a number of other arrays.
   // Only the elements present in just the first array will remain.
-  _.difference = function(array, other) {
-    return _.filter(array, function(value){ return !_.include(other, value); });
+  _.difference = function(array) {
+    var rest = _.flatten(slice.call(arguments, 1));
+    return _.filter(array, function(value){ return !_.include(rest, value); });
   };
 
   // Zip together multiple lists into a single array -- elements that share
@@ -387,17 +431,16 @@
       return array[i] === item ? i : -1;
     }
     if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item);
-    for (i = 0, l = array.length; i < l; i++) if (array[i] === item) return i;
+    for (i = 0, l = array.length; i < l; i++) if (i in array && array[i] === item) return i;
     return -1;
   };
 
-
   // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available.
   _.lastIndexOf = function(array, item) {
     if (array == null) return -1;
     if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) return array.lastIndexOf(item);
     var i = array.length;
-    while (i--) if (array[i] === item) return i;
+    while (i--) if (i in array && array[i] === item) return i;
     return -1;
   };
 
@@ -426,15 +469,25 @@
   // Function (ahem) Functions
   // ------------------
 
+  // Reusable constructor function for prototype setting.
+  var ctor = function(){};
+
   // Create a function bound to a given object (assigning `this`, and arguments,
   // optionally). Binding with arguments is also known as `curry`.
   // Delegates to **ECMAScript 5**'s native `Function.bind` if available.
   // We check for `func.bind` first, to fail fast when `func` is undefined.
-  _.bind = function(func, obj) {
+  _.bind = function bind(func, context) {
+    var bound, args;
     if (func.bind === nativeBind && nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
-    var args = slice.call(arguments, 2);
-    return function() {
-      return func.apply(obj, args.concat(slice.call(arguments)));
+    if (!_.isFunction(func)) throw new TypeError;
+    args = slice.call(arguments, 2);
+    return bound = function() {
+      if (!(this instanceof bound)) return func.apply(context, args.concat(slice.call(arguments)));
+      ctor.prototype = func.prototype;
+      var self = new ctor;
+      var result = func.apply(self, args.concat(slice.call(arguments)));
+      if (Object(result) === result) return result;
+      return self;
     };
   };
 
@@ -453,7 +506,7 @@
     hasher || (hasher = _.identity);
     return function() {
       var key = hasher.apply(this, arguments);
-      return hasOwnProperty.call(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
+      return _.has(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
     };
   };
 
@@ -470,31 +523,43 @@
     return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
   };
 
-  // Internal function used to implement `_.throttle` and `_.debounce`.
-  var limit = function(func, wait, debounce) {
-    var timeout;
-    return function() {
-      var context = this, args = arguments;
-      var throttler = function() {
-        timeout = null;
-        func.apply(context, args);
-      };
-      if (debounce) clearTimeout(timeout);
-      if (debounce || !timeout) timeout = setTimeout(throttler, wait);
-    };
-  };
-
   // Returns a function, that, when invoked, will only be triggered at most once
   // during a given window of time.
   _.throttle = function(func, wait) {
-    return limit(func, wait, false);
+    var context, args, timeout, throttling, more;
+    var whenDone = _.debounce(function(){ more = throttling = false; }, wait);
+    return function() {
+      context = this; args = arguments;
+      var later = function() {
+        timeout = null;
+        if (more) func.apply(context, args);
+        whenDone();
+      };
+      if (!timeout) timeout = setTimeout(later, wait);
+      if (throttling) {
+        more = true;
+      } else {
+        func.apply(context, args);
+      }
+      whenDone();
+      throttling = true;
+    };
   };
 
   // Returns a function, that, as long as it continues to be invoked, will not
   // be triggered. The function will be called after it stops being called for
   // N milliseconds.
   _.debounce = function(func, wait) {
-    return limit(func, wait, true);
+    var timeout;
+    return function() {
+      var context = this, args = arguments;
+      var later = function() {
+        timeout = null;
+        func.apply(context, args);
+      };
+      clearTimeout(timeout);
+      timeout = setTimeout(later, wait);
+    };
   };
 
   // Returns a function that will be executed at most one time, no matter how
@@ -513,7 +578,7 @@
   // conditionally execute the original function.
   _.wrap = function(func, wrapper) {
     return function() {
-      var args = [func].concat(slice.call(arguments));
+      var args = [func].concat(slice.call(arguments, 0));
       return wrapper.apply(this, args);
     };
   };
@@ -521,9 +586,9 @@
   // Returns a function that is the composition of a list of functions, each
   // consuming the return value of the function that follows.
   _.compose = function() {
-    var funcs = slice.call(arguments);
+    var funcs = arguments;
     return function() {
-      var args = slice.call(arguments);
+      var args = arguments;
       for (var i = funcs.length - 1; i >= 0; i--) {
         args = [funcs[i].apply(this, args)];
       }
@@ -533,12 +598,12 @@
 
   // Returns a function that will only be executed after being called N times.
   _.after = function(times, func) {
+    if (times <= 0) return func();
     return function() {
       if (--times < 1) { return func.apply(this, arguments); }
     };
   };
 
-
   // Object Functions
   // ----------------
 
@@ -547,7 +612,7 @@
   _.keys = nativeKeys || function(obj) {
     if (obj !== Object(obj)) throw new TypeError('Invalid object');
     var keys = [];
-    for (var key in obj) if (hasOwnProperty.call(obj, key)) keys[keys.length] = key;
+    for (var key in obj) if (_.has(obj, key)) keys[keys.length] = key;
     return keys;
   };
 
@@ -570,7 +635,7 @@
   _.extend = function(obj) {
     each(slice.call(arguments, 1), function(source) {
       for (var prop in source) {
-        if (source[prop] !== void 0) obj[prop] = source[prop];
+        obj[prop] = source[prop];
       }
     });
     return obj;
@@ -588,6 +653,7 @@
 
   // Create a (shallow-cloned) duplicate of an object.
   _.clone = function(obj) {
+    if (!_.isObject(obj)) return obj;
     return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
   };
 
@@ -599,50 +665,104 @@
     return obj;
   };
 
-  // Perform a deep comparison to check if two objects are equal.
-  _.isEqual = function(a, b) {
-    // Check object identity.
-    if (a === b) return true;
-    // Different types?
-    var atype = typeof(a), btype = typeof(b);
-    if (atype != btype) return false;
-    // Basic equality test (watch out for coercions).
-    if (a == b) return true;
-    // One is falsy and the other truthy.
-    if ((!a && b) || (a && !b)) return false;
+  // Internal recursive comparison function.
+  function eq(a, b, stack) {
+    // Identical objects are equal. `0 === -0`, but they aren't identical.
+    // See the Harmony `egal` proposal: http://wiki.ecmascript.org/doku.php?id=harmony:egal.
+    if (a === b) return a !== 0 || 1 / a == 1 / b;
+    // A strict comparison is necessary because `null == undefined`.
+    if (a == null || b == null) return a === b;
     // Unwrap any wrapped objects.
     if (a._chain) a = a._wrapped;
     if (b._chain) b = b._wrapped;
-    // One of them implements an isEqual()?
-    if (a.isEqual) return a.isEqual(b);
-    if (b.isEqual) return b.isEqual(a);
-    // Check dates' integer values.
-    if (_.isDate(a) && _.isDate(b)) return a.getTime() === b.getTime();
-    // Both are NaN?
-    if (_.isNaN(a) && _.isNaN(b)) return false;
-    // Compare regular expressions.
-    if (_.isRegExp(a) && _.isRegExp(b))
-      return a.source     === b.source &&
-             a.global     === b.global &&
-             a.ignoreCase === b.ignoreCase &&
-             a.multiline  === b.multiline;
-    // If a is not an object by this point, we can't handle it.
-    if (atype !== 'object') return false;
-    // Check for different array lengths before comparing contents.
-    if (a.length && (a.length !== b.length)) return false;
-    // Nothing else worked, deep compare the contents.
-    var aKeys = _.keys(a), bKeys = _.keys(b);
-    // Different object sizes?
-    if (aKeys.length != bKeys.length) return false;
-    // Recursive comparison of contents.
-    for (var key in a) if (!(key in b) || !_.isEqual(a[key], b[key])) return false;
-    return true;
+    // Invoke a custom `isEqual` method if one is provided.
+    if (a.isEqual && _.isFunction(a.isEqual)) return a.isEqual(b);
+    if (b.isEqual && _.isFunction(b.isEqual)) return b.isEqual(a);
+    // Compare `[[Class]]` names.
+    var className = toString.call(a);
+    if (className != toString.call(b)) return false;
+    switch (className) {
+      // Strings, numbers, dates, and booleans are compared by value.
+      case '[object String]':
+        // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is
+        // equivalent to `new String("5")`.
+        return a == String(b);
+      case '[object Number]':
+        // `NaN`s are equivalent, but non-reflexive. An `egal` comparison is performed for
+        // other numeric values.
+        return a != +a ? b != +b : (a == 0 ? 1 / a == 1 / b : a == +b);
+      case '[object Date]':
+      case '[object Boolean]':
+        // Coerce dates and booleans to numeric primitive values. Dates are compared by their
+        // millisecond representations. Note that invalid dates with millisecond representations
+        // of `NaN` are not equivalent.
+        return +a == +b;
+      // RegExps are compared by their source patterns and flags.
+      case '[object RegExp]':
+        return a.source == b.source &&
+               a.global == b.global &&
+               a.multiline == b.multiline &&
+               a.ignoreCase == b.ignoreCase;
+    }
+    if (typeof a != 'object' || typeof b != 'object') return false;
+    // Assume equality for cyclic structures. The algorithm for detecting cyclic
+    // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
+    var length = stack.length;
+    while (length--) {
+      // Linear search. Performance is inversely proportional to the number of
+      // unique nested structures.
+      if (stack[length] == a) return true;
+    }
+    // Add the first object to the stack of traversed objects.
+    stack.push(a);
+    var size = 0, result = true;
+    // Recursively compare objects and arrays.
+    if (className == '[object Array]') {
+      // Compare array lengths to determine if a deep comparison is necessary.
+      size = a.length;
+      result = size == b.length;
+      if (result) {
+        // Deep compare the contents, ignoring non-numeric properties.
+        while (size--) {
+          // Ensure commutative equality for sparse arrays.
+          if (!(result = size in a == size in b && eq(a[size], b[size], stack))) break;
+        }
+      }
+    } else {
+      // Objects with different constructors are not equivalent.
+      if ('constructor' in a != 'constructor' in b || a.constructor != b.constructor) return false;
+      // Deep compare objects.
+      for (var key in a) {
+        if (_.has(a, key)) {
+          // Count the expected number of properties.
+          size++;
+          // Deep compare each member.
+          if (!(result = _.has(b, key) && eq(a[key], b[key], stack))) break;
+        }
+      }
+      // Ensure that both objects contain the same number of properties.
+      if (result) {
+        for (key in b) {
+          if (_.has(b, key) && !(size--)) break;
+        }
+        result = !size;
+      }
+    }
+    // Remove the first object from the stack of traversed objects.
+    stack.pop();
+    return result;
+  }
+
+  // Perform a deep comparison to check if two objects are equal.
+  _.isEqual = function(a, b) {
+    return eq(a, b, []);
   };
 
-  // Is a given array or object empty?
+  // Is a given array, string, or object empty?
+  // An "empty" object has no enumerable own-properties.
   _.isEmpty = function(obj) {
     if (_.isArray(obj) || _.isString(obj)) return obj.length === 0;
-    for (var key in obj) if (hasOwnProperty.call(obj, key)) return false;
+    for (var key in obj) if (_.has(obj, key)) return false;
     return true;
   };
 
@@ -654,7 +774,7 @@
   // Is a given value an array?
   // Delegates to ECMA5's native Array.isArray
   _.isArray = nativeIsArray || function(obj) {
-    return toString.call(obj) === '[object Array]';
+    return toString.call(obj) == '[object Array]';
   };
 
   // Is a given variable an object?
@@ -664,43 +784,48 @@
 
   // Is a given variable an arguments object?
   _.isArguments = function(obj) {
-    return !!(obj && hasOwnProperty.call(obj, 'callee'));
+    return toString.call(obj) == '[object Arguments]';
   };
+  if (!_.isArguments(arguments)) {
+    _.isArguments = function(obj) {
+      return !!(obj && _.has(obj, 'callee'));
+    };
+  }
 
   // Is a given value a function?
   _.isFunction = function(obj) {
-    return !!(obj && obj.constructor && obj.call && obj.apply);
+    return toString.call(obj) == '[object Function]';
   };
 
   // Is a given value a string?
   _.isString = function(obj) {
-    return !!(obj === '' || (obj && obj.charCodeAt && obj.substr));
+    return toString.call(obj) == '[object String]';
   };
 
   // Is a given value a number?
   _.isNumber = function(obj) {
-    return !!(obj === 0 || (obj && obj.toExponential && obj.toFixed));
+    return toString.call(obj) == '[object Number]';
   };
 
-  // Is the given value `NaN`? `NaN` happens to be the only value in JavaScript
-  // that does not equal itself.
+  // Is the given value `NaN`?
   _.isNaN = function(obj) {
+    // `NaN` is the only value for which `===` is not reflexive.
     return obj !== obj;
   };
 
   // Is a given value a boolean?
   _.isBoolean = function(obj) {
-    return obj === true || obj === false;
+    return obj === true || obj === false || toString.call(obj) == '[object Boolean]';
   };
 
   // Is a given value a date?
   _.isDate = function(obj) {
-    return !!(obj && obj.getTimezoneOffset && obj.setUTCFullYear);
+    return toString.call(obj) == '[object Date]';
   };
 
   // Is the given value a regular expression?
   _.isRegExp = function(obj) {
-    return !!(obj && obj.test && obj.exec && (obj.ignoreCase || obj.ignoreCase === false));
+    return toString.call(obj) == '[object RegExp]';
   };
 
   // Is a given value equal to null?
@@ -713,6 +838,11 @@
     return obj === void 0;
   };
 
+  // Has own property?
+  _.has = function(obj, key) {
+    return hasOwnProperty.call(obj, key);
+  };
+
   // Utility Functions
   // -----------------
 
@@ -733,6 +863,11 @@
     for (var i = 0; i < n; i++) iterator.call(context, i);
   };
 
+  // Escape a string for HTML interpolation.
+  _.escape = function(string) {
+    return (''+string).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;').replace(/'/g, '&#x27;').replace(/\//g,'&#x2F;');
+  };
+
   // Add your own custom functions to the Underscore object, ensuring that
   // they're correctly added to the OOP wrapper as well.
   _.mixin = function(obj) {
@@ -753,7 +888,19 @@
   // following template settings to use alternative delimiters.
   _.templateSettings = {
     evaluate    : /<%([\s\S]+?)%>/g,
-    interpolate : /<%=([\s\S]+?)%>/g
+    interpolate : /<%=([\s\S]+?)%>/g,
+    escape      : /<%-([\s\S]+?)%>/g
+  };
+
+  // When customizing `templateSettings`, if you don't want to define an
+  // interpolation, evaluation or escaping regex, we need one that is
+  // guaranteed not to match.
+  var noMatch = /.^/;
+
+  // Within an interpolation, evaluation, or escaping, remove HTML escaping
+  // that had been previously added.
+  var unescape = function(code) {
+    return code.replace(/\\\\/g, '\\').replace(/\\'/g, "'");
   };
 
   // JavaScript micro-templating, similar to John Resig's implementation.
@@ -765,19 +912,29 @@
       'with(obj||{}){__p.push(\'' +
       str.replace(/\\/g, '\\\\')
          .replace(/'/g, "\\'")
-         .replace(c.interpolate, function(match, code) {
-           return "'," + code.replace(/\\'/g, "'") + ",'";
+         .replace(c.escape || noMatch, function(match, code) {
+           return "',_.escape(" + unescape(code) + "),'";
          })
-         .replace(c.evaluate || null, function(match, code) {
-           return "');" + code.replace(/\\'/g, "'")
-                              .replace(/[\r\n\t]/g, ' ') + "__p.push('";
+         .replace(c.interpolate || noMatch, function(match, code) {
+           return "'," + unescape(code) + ",'";
+         })
+         .replace(c.evaluate || noMatch, function(match, code) {
+           return "');" + unescape(code).replace(/[\r\n\t]/g, ' ') + ";__p.push('";
          })
          .replace(/\r/g, '\\r')
          .replace(/\n/g, '\\n')
          .replace(/\t/g, '\\t')
          + "');}return __p.join('');";
-    var func = new Function('obj', tmpl);
-    return data ? func(data) : func;
+    var func = new Function('obj', '_', tmpl);
+    if (data) return func(data, _);
+    return function(data) {
+      return func.call(this, data, _);
+    };
+  };
+
+  // Add a "chain" function, which will delegate to the wrapper.
+  _.chain = function(obj) {
+    return _(obj).chain();
   };
 
   // The OOP Wrapper
@@ -812,8 +969,11 @@
   each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
     var method = ArrayProto[name];
     wrapper.prototype[name] = function() {
-      method.apply(this._wrapped, arguments);
-      return result(this._wrapped, this._chain);
+      var wrapped = this._wrapped;
+      method.apply(wrapped, arguments);
+      var length = wrapped.length;
+      if ((name == 'shift' || name == 'splice') && length === 0) delete wrapped[0];
+      return result(wrapped, this._chain);
     };
   });
 
@@ -836,4 +996,4 @@
     return this._wrapped;
   };
 
-})();
+}).call(this);