Fixed pecl/ibm_db2 Driver and Connection to run smoothly against the complete test-suite (depending on a c-patch to the extension though)

DDC-496 Finished first versions of platform and schema manager for DB2, DDC-528 Added support for PDO_IBM driver, passing all but 3 tests that are related to CLOB fields

[2.0] DDC-341 - Added Composite Model-Set and 3 tests, fixed two bugs in SqlWalker with Composite Key support

[2.0] DDC-342 - Throw Exception with notice in case of Many To Many relation pointing to Joined Inheritance Hierachy until this feature is completed

[2.0] DDC-341 - Added Composite Model-Set and 3 tests, fixed two bugs in SqlWalker with Composite Key support

[2.0] DDC-484 - Fix reference to Doctrine\ORM\ORMException in ProxyException, added two unit-tests for missing tests of ProxyException throws

[2.0] Fixed and added some missing/wrong docblocks. Renamed Assigned to AssignedGenerator as scheduled to be renamed.

[2.0][DDC-354][DDC-425] Fixed. Encapsulated SQL logging better in the DBAL. Added binding types to DBAL mapping types as well as using these binding types in the persisters. Query and NativeQuery now support PDO binding types as well as DBAL mapping types when binding parameters.

[2.0] More fixes to EntityGenerator. Coding standard fixes and improved error reporting on invalid arguments provided.