[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] 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] Updating sandbox cli to use APC again but adding comment to use ArrayCache if APC is not available

[2.0] Changing sandbox to use ArrayCache by default so it doesn't require APC. Added comment with APC as the recommended for production

[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] Work on CLI: Added SchemaToolTask with preliminary support for dropping/creating the database schema. Prepared the sandbox. Adjusted build to include the sandbox.

Refactorings for schema files and Doctrine_Record builder. More to come but got held up on some things that zYne- must fix first.