[2.0] DDC-169 - Changed AbstractPlatform and AbstractSchemaManager and children to accept Table, Index and ForeignKey instances for the respective create*() methods.

[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] Test coverage for OFFSET AND LIMIT sql generation for all platforms and Query class with setFirstResult() and setMaxResult()

divided some assertions in various cohesive methods and renamed method names to conform to agile documentation (affects #2316)

[2.0] Introduced SQL logging facilities. Made Type constructor private to prevent instantiation and force use of the factory method getType().

[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.