Initial implementation of Model and Restful storage
Add Models class

It is used for retrieving right factory by Model type, to avoid creating
factory objects all the time. Kudos to @danschultz for the idea. :)
Add has many associations support
Change API of associations
Rename ModelFactory to ModelConnector
Rename collection to findAll
Merge pull request #1 from Mixbook/first-draft

Initial implementation of Model and Restful storage