Trigger change events for radio and checkbox items. Currently, no .on('change'...) is fired if the model causes an update. This is necessary for widgets and listeners acting directly on the checkbox/radio items.

The change triggers must be deferred, however, or the old model value is actually thrown out to test units (and presumably public listeners).
Fixes theironcook/Backbone.ModelBinder#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.