[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-22] Fixed. Also cleaned up association handling. More to come: exception refactorings, proxy simplifications (single proxy class, not two).

[2.0] Some work over SchemaTool update of schema (affects directly the CLI schema-tool task on --update option.

[2.0] Refactored pieces of QueryBuilder, it does not use string concatenation anymore. Splitted from into from and join, allowing update and delete DQLs to be correctly built. Added missing entry set. Removed Expr\Having because it was useless. Updated docs.

[2.0] Applied fixes for character casing issues. Simplified inheritance mapping and improved handling of outer joins in Class Table Inheritance.

[2.0] Removed AssociationMappings from ResultSetMapping  for improved caching. Fixed caching issue with reflection classes and properties. Reimplemented and leaned up broken identifier quoting. Added support for named (native) queries. Fixed small hydration memory leak.

[2.0] Accomodate joincolumn names in the metadata, in the selection and the hydration processes. Improved Api of the ProxyFactory. Working implementation of lazy loading for *-to-one associations (affects #2348)

[2.0] Moved locking tests into Functional namespace. Fixed several missing flush() calls in some functional association tests. Reordered DELETE statements for ecommerce model tests in OrmFunctionalTestCase in order to maintain referential integrity. Fixed issue with bi-directional self-referencing one-one associations. Some other small improvements and cosmetics. Small hydration performance improvement through inlining method call in UnitOfWork::createEntity().

[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] Fixes and enhancements to sequence generators. Test suite now runs & passes against postgres. Other minor, unrelated cleanups.

[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.