Use coffee-script node module

This required upgrading underscore which to fix issues
with _.isEqual working across objects created from different
documents.

The upgrade required adding a custom _.isEqual extension that
added back support for object's having an isEqual method that
was removed in underscore 1.4.0.

src/packages/snippets/lib/snippet-expansion.coffee

@@ -27,7 +27,7 @@ class SnippetExpansion
     return if @settingTabStop or bufferChanged
     oldTabStops = @tabStopsForBufferPosition(oldBufferPosition)
     newTabStops = @tabStopsForBufferPosition(newBufferPosition)
-    @destroy() unless _.intersect(oldTabStops, newTabStops).length
+    @destroy() unless _.intersection(oldTabStops, newTabStops).length
 
   placeTabStopMarkers: (startPosition, tabStopRanges) ->
     @tabStopMarkers = tabStopRanges.map ({start, end}) =>

src/stdlib/fs.coffee

@@ -218,7 +218,7 @@ module.exports =
   readObject: (path) ->
     contents = @read(path)
     if @extension(path) is '.cson'
-      {CoffeeScript} = require 'coffee-script'
+      CoffeeScript = nodeRequire 'coffee-script'
       CoffeeScript.eval(contents, bare: true)
     else
       JSON.parse(contents)

src/stdlib/require.coffee

@@ -61,7 +61,7 @@ exts =
       compiled = __read(cacheFilePath)
       writeToCache = false
     else
-      {CoffeeScript} = require 'coffee-script'
+      CoffeeScript = nodeRequire 'coffee-script'
       compiled = CoffeeScript.compile(__read(file), filename: file)
       writeToCache = true
 
@@ -76,7 +76,7 @@ getPath = (path) ->
 
   cacheFilePath = getCacheFilePath(path)
   unless __exists(cacheFilePath)
-    {CoffeeScript} = require 'coffee-script'
+    CoffeeScript = nodeRequire 'coffee-script'
     compiled = CoffeeScript.compile(__read(path), filename: path)
     createCacheDirectory()
     fs.writeFileSync(cacheFilePath, compiled)

src/stdlib/settings.coffee

@@ -1,5 +1,5 @@
 fs = require 'fs'
-{CoffeeScript} = require 'coffee-script'
+CoffeeScript = require 'coffee-script'
 
 # Settings file looks like:
 #     editor: # name of class

src/stdlib/underscore-extensions.coffee

@@ -131,3 +131,53 @@ _.mixin
     for key, value of object
       newObject[key] = value if value?
     newObject
+
+originalIsEqual = _.isEqual
+extendedIsEqual = (a, b, aStack=[], bStack=[]) ->
+  return originalIsEqual(a, b) if a is b
+  return originalIsEqual(a, b) if _.isFunction(a) or _.isFunction(b)
+  return a.isEqual(b) if _.isFunction(a?.isEqual)
+  return b.isEqual(a) if _.isFunction(b?.isEqual)
+
+  stackIndex = aStack.length
+  while stackIndex--
+    return bStack[stackIndex] is b if aStack[stackIndex] is a
+  aStack.push(a)
+  bStack.push(b)
+
+  equal = false
+  if _.isArray(a) and _.isArray(b) and a.length is b.length
+    equal = true
+    for aElement, i in a
+      unless extendedIsEqual(aElement, b[i], aStack, bStack)
+        equal = false
+        break
+  else if _.isObject(a) and _.isObject(b)
+    aCtor = a.constructor
+    bCtor = b.constructor
+    aCtorValid = _.isFunction(aCtor) and aCtor instanceof aCtor
+    bCtorValid = _.isFunction(bCtor) and bCtor instanceof bCtor
+    if aCtor isnt bCtor and not (aCtorValid and bCtorValid)
+      equal = false
+    else
+      aKeyCount = 0
+      equal = true
+      for key, aValue of a
+        continue unless _.has(a, key)
+        aKeyCount++
+        unless _.has(b, key) and extendedIsEqual(aValue, b[key], aStack, bStack)
+          equal = false
+          break
+      if equal
+        bKeyCount = 0
+        for key, bValue of b
+          bKeyCount++ if _.has(b, key)
+        equal = aKeyCount is bKeyCount
+  else
+    equal = originalIsEqual(a, b)
+
+  aStack.pop()
+  bStack.pop()
+  equal
+
+_.isEqual = (a, b) -> extendedIsEqual(a, b)