Function: registerCollection
Registers a specific <Barefoot.Collection> and the <Barefoot.Model>s which
are contained in it with the given identifier. This information is needed
when serializing the DataStore for transferring data to the client.

You will not be able to serialize a store containing collections which were
not registered before!

Important:
Do not register "instances" of a collection. Instead, register its "class".

Parameters:
(String) identifier - A unique identifier for this collection type
(Barefoot.Collection) collection - Collection type
(Barefoot.Model) model - Model type contained in the collection
function registerCollection(identifier, collection, model) {
	this.registeredModelsAndCollections[identifier] = {
		collectionClass: collection
		, modelClass: model
	};
}