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

[2.0] Moved cache drivers to Common package. Added new annotation parser implementation to Common package. AnnotationDriver in ORM not yet migrated.