[2.0][DDC-122][DDC-97][DDC-98][DDC-147] Refactored metadata mapping drivers by removing the useless PRELOAD mode. Introduced ClassMetadataFactory#getAllMetadata. Classloader simplifications. Old classloaders deprecated. New Doctrine\Common\ClassLoader is almost the same as the previous IsolatedClassLoader.

[2.0] More refactorings in Annotations parser and DQL parser. Now they only use constants instead of string processment

[2.0] DDC-78 - Added support for context specific information in Annotation Parser Syntax Error Exceptions.

[2.0] Added test that shows AnnotationParser only parses string literals with double quotes, wheras single quotes throw an Syntax Error. Removed debug output on failure for a proper syntax error exception.

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

[2.0] Small refactorings on the cache drivers. Introduced flag to control whether the cache driver should manage the cache keys since this is an advanced feature that is not always needed and can have negative side-effects (higher probability for cache slams).

[2.0][DDC-48][DDC-47] Refactored cache drivers to allow more control over deleting, added namespacing to cache drivers and implemented clear-cache task

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

[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] Refactored classloader architecture. Renamed ClassLoader => GlobalClassLoader. Introduced IsolatedClassLoader that is suitable for participating in autoload stacks. Added 2 example entity classes to the sandbox with 2 xml mappings and 2 yaml mappings. Simplified sandbox setup.

[2.0] Removed xdebug builtin support from Debug::dump(). Added run-dql CLI Task. Updated tasks to wrap Exceptions thrown and diplay nicely. Fixed bug with CLI that ws incorrectly splitting strings into an array instead of consider them raw.

[2.0] Updated description for pear packages. Enhanced ClassLoader to support the old namespace separator (underscore) for Zend/PEAR/... compatibility until some day when they all use 5.3+.

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

[2.0] Fixed several referential integrity issues. Fixed critical issue with inserts being run twice on postgresql/oracle. Added support for additional tree walkers that modify the AST prior to SQL construction and started to play with it in a testcase.

[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] Added more missing docblocks. Implemented a double-inclusion listener prevention in EventManager

[2.0] Some Annotations parser docblocks, optimizations, etc. Fixed wrong syntax error token report in DQL parser

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