[2.0] Grammar rule fixes to prevent possibility to do key=field=identifier as a correct parseable grammar

[2.0] Fixed hydration issue with bidirectional one-to-many associations. Added more test coverage for some advanced association queries and lazy-loading.

[2.0][DDC-49][DDC-50][DDC-33] Fixed DDC-49 and DDC-50. Also addressed DDC-33. Various other small changes and fixes. For problems with proxy objects please refer to the updated documentation.

[2.0] DBAL cleanups (DDC-46). Proxy class improvements (DDC-19, DDC-39). Started new UPGRADE_TO document for upgrade instructions between advancing Doctrine 2 versions.

[2.0] Refactoring some common code in to the AnnotationDriver and creating PhpDriver for consistancy

[2.0][DDC-34] Fixing issue with duplicate association mappings when dealing with mapped super classes

[2.0] Added functionality to convert a Doctrine 1 schema to Doctrine 2 to help users with upgrading. Lots of other small bug fixes and changes.

[2.0] Added jpgraph.php script that can be used to visualize logs of phpunit test runs with graphs using jpgraph. The graphs show the performance of tests over the revisions.