Updated Bacon.js

Added parse option to Collection's `add`

Improved Model saving to wailt for server response

Refactored utilities

Simplified `attributes` extension for collection models

Refined API with Bacon extension instead of specific methods

Fixed a problem with Collection's `add` method that was incorrectly adding element twice when also updating some other element

Added merge and update options to Collection's `add` method

Better hanling of Collection shortcut methods arguments parsing

Added `fetc` to Collection. Fixed behaviour of `fetch` and `save` for Model

Better Collection's models accessors api

Changed `models` api to always send an array. Added `modelsAttributes` method to Collections.

Fixed `validModels` behaviour with parameters

Updated Bacon.js

Fixed reset for Collection; it wasn't removing collection reference in models