Interfaces, Associator, AbstractRepository

I didn't change so much, I added an Abstract Repository, a simple Associator for class->worker, and few Interfaces 

- IdentityMapSynchronizerInterface
- IdentityExtractorFactoryInterface
- ObjectLoaderFactoryInterface
- ObjectRepositoryFactoryInterface
- ObjectRepositoryInterface

let me know what do you think, with the interface I created a stupid orm.