[2.0] Merged PreInsertEventArgs/PreUpdateEventArgs => PreInsertUpdateEventArgs since they were identical.

[2.0] Fixed issue with self-referential one-to-many associations not being persisted correctly when IDENTITY key generation was used. Included now passing OneToManySelfReferentialTest.

[2.0] Implemented DQL bulk UPDATE support for Class Table Inheritance. Corrections to MultiTableDeleteExecutor and SqlWalker. DQL bulk UPDATE support not yet fully complete.

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

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

[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.

[2.0] Refactored SQL query building process and hydration. Hydration should now support result sets with any number of root components. Introducing ResultSetMapping that is used by hydration instead of queryComponents. This allows mapping of arbitrary SQL queries (NativeQuery).

[2.0] Parser work. Drafted logic for multi-table deletes through DQL (for Class/Concrete Table Inheritance)