[AC-1636] Collection.get returns null when searching by cid

Alloy.Collections.cars.reset([{'make':'Honda'}, {'make':'Ford'}]);

// Imagine that we want to get an item by the 'cid' that backbone creates for each item in the collection.
// So if we do that, it returns null. Im using right now getByCid but on Titanium SDK 3.5.1.G.A 
// and it works but since Backbone deprecate it.. we have to use the get directly on 4.0.0RC4/5
// If you try to replicate this behaviour with Backbone itself, you´ll see how it works but not on Alloy actually. 
Alloy.Collections.cars.get('c1');