[2.0] Implemented DQL bulk DELETE support for Class Table Inheritance. Other cleanups, refactorings and docblock additions.

[2.0] Solved the hassle with dropping/creating the test database through introducing a second test database for temporary connections. Please check the dbproperties.xml.dev file for reference. The 2 test databases need to be created *once* before the very first time of running the tests. New procedure successfully tested against mysql, postgresql, oracle.

[2.0] Adjusted getConnection since there is no need to create/drop the database for sqlite in-memory.

[2.0] Changed identifier quoting strategy to something simpler. Dropped Doctrine prefix from annotations.