Implemented support for RepositoryFactory.
Merge pull request #694 from FabioBatSilva/DDC-2478

[DDC-2478] Support null association comparison
Fixed wrong interface.
Reducing dependency on RepositoryFactory by providing EntityManager as a getRepository argument.
Reduced granularity of DefaultRepositoryFactory reference to ObjectRepository instances, in cases where consumers are completely rewrote EntityRepository.
Fix phpDoc syntax in ClassMetadataInfo.php
Merge pull request #697 from michaelperrin/patch-1

Fix phpDoc syntax in ClassMetadataInfo.php
Updated since php doc tag.
Merge pull request #695 from doctrine/RepositoryFactory

Implemented support for RepositoryFactory.
Second cache level POC
First round of refactory
Fix factory method name
refactoring region access tests
basically support for many to many collection
Refactoring tests
store cascade collections
refactoring collections store
handle one to many collections storage
tests put entities on persist
test one to many orphan removal