Fixes theironcook#131

Optimize CollectionBinder::getManagerForModel to use keyed values already stored internally.

defaultBindings was generating a js error; this did not cause any test cases to fail because it occurred after test cases completed. However, since the checkboxes return boolean values, there is no .replace value available; corrected.

Backbone.CollectionBinder.js

@@ -71,17 +71,7 @@
         },
 
         getManagerForModel: function(model){
-            var i, elManager, elManagers = _.values(this._elManagers);
-
-            for(i = 0; i < elManagers.length; i++){
-                elManager = elManagers[i];
-
-                if(elManager.getModel() === model){
-                    return elManager;
-                }
-            }
-
-            return undefined;
+           return this._elManagers[_.isObject(model)? model.cid : model];
         },
 
         _onCollectionAdd: function(model){

spec/javascripts/defaultBindings.spec.js

@@ -74,12 +74,12 @@ describe('default bindings', function(){
         });
 
         it('converter bindings', function(){
-            var defaultConverter = function(direction, value){
+            var defaultConverter = function(direction, value, key){
                 if(direction === Backbone.ModelBinder.Constants.ModelToView){
-                    return 'XXX' + value;
+                    return key === 'isActive'? value : 'XXX' + value;
                 }
                 else {
-                    return value.replace('XXX');
+                    return _.isString(value)? value.replace('XXX') : value;
                 }
             };