[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.

[2.0][DDC-30] Fixed null values with Date, Time and DateTime types. Thanks Ismo for report and patch

[2.0][DDC-23] Implemented setFirstResult, getFirstResult aswell as setMaxResults and getMaxResults in QueryBuilder

[2.0] More work on ClassmetadataExporter and ConvertMappingTask for converting mapping information between various formats