Merge pull request #3625 from jridgewell/model-isValid-style

Use defaults in #isValid

backbone.js

@@ -699,7 +699,7 @@
 
     // Check if the model is currently in a valid state.
     isValid: function(options) {
-      return this._validate({}, _.extend(options || {}, { validate: true }));
+      return this._validate({}, _.defaults({validate: true}, options));
     },
 
     // Run validation against the next complete set of model attributes,