DDC-178 - Fixed problems occuring from merging upstream, re-ran API and tests, finalizing lock-support for merge with upstream

DDC-515 - Enhanced Validate-Schema-Command, integrated it with CLI and besides mapping<->database checks also do consistency checks of the mapping files

Also added a new testcase

Conflicts:

	lib/Doctrine/ORM/Mapping/Driver/XmlDriver.php

Removed EntityTransaction until it has a real purpose. Added the affected entity to OptimisticLockException. Updated functional optimistic locking tests accordingly.

Renamed fetchRow to fetchAssoc, as defined in @todo list. Renamed getRollbackOnly to isRollbackOnly, since it is more consistent to its purpose.

Revertd partially the support to DBAL\Transaction, it was wrong. Fixed implementation of ORM\EntityTransaction and fixed tests.