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-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] Improving EntityGenerated: added normal doc blocks above annotations(even if annotations aren't generated), adding type hinting, added generation of default values for properties

[2.0] Code cleanups. Preparations for DDC-193. Fixed DDC-399, type configuration remains global for now but the irritating instance methods on the Configuration have been removed. Use Type::addType et al. Added TODOs for naming standards.

[2.0][DDC-92] Fixed. Patch provided by Christian Heinrich. [DDC-274] Started some method renaming. [DDC-142] Fixed (join column names and discriminator column names dont support quoting) [DDC-258] Fixed.

[2.0] DDC-365 -  Added tests for several missing column types - also showing that decimals come and go correctly into the database.

DDC-179 - Fixed issue with persistance of date fields by moving ! operator to the convertToPhpValue method.

[2.0][DDC-164][DDC-165] Fixed. Cleaned up ManyToManyMapping. Cleaned up identifier handling and handling of composite identifiers in some places.

[2.0][DDC-30] Fixed null values with Date, Time and DateTime types. Thanks Ismo for report and patch

[2.0] Various necessary fixes and adjustments for oracle as well as fixes for better handling of temporal types. Closed #2452.

[2.0] More docblocks. Renamed methods Type::addCustomType to Type::addType and Connection::exec to Connection::executeUpdate. Added Type::hasType.

[2.0] Streamlined result structures. Hydration improvements: Small overall improvements, large improvement for (joined) fetched collections (~60%). 

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

[2.0] Introduced SQL logging facilities. Made Type constructor private to prevent instantiation and force use of the factory method getType().

[2.0] Fixed issues discovered during code coverage report generation. Made all ClassMetadata properties public (good reasons, read the class docblock). Performance improvements.

[2.0] Started to implement proxy object handling. Introduced a configuration switch for partial objects (allowPartialObjects) that defaults to TRUE. Setting to FALSE enables proxying and lazy-loading.

[2.0] Moved code between Query and AbstractQuery. Added first NativeQuery implementation. Hydration work and code movements for discriminator column usage. Started implementing Single Table Inheritance.