Override base Backbone Model and Collection.

 On branch dashboard_ent_caching
	new file:   app/assets/javascripts/backbone/lib/concerns/entity/collection_fetch.js.coffee
	new file:   app/assets/javascripts/backbone/lib/concerns/entity/model_fetch.js.coffee
Start of entity cache.

 On branch dashboard_ent_caching
	modified:   app/assets/javascripts/backbone/lib/concerns/entity/collection_fetch.js.coffee
	modified:   app/assets/javascripts/backbone/lib/concerns/entity/fetch_updates.js.coffee
	modified:   app/assets/javascripts/backbone/lib/concerns/entity/model_fetch.js.coffee
	new file:   app/assets/javascripts/backbone/lib/entities/cache.js.coffee
	deleted:    app/assets/javascripts/backbone/lib/entities/collection_manager.js.coffee