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

[2.0] Some work over SchemaTool update of schema (affects directly the CLI schema-tool task on --update option.

[2.0] Fixing spacing and adding precision and scale in Annotations driver. Also introduced options item in Annotation and Yaml mapping drivers. Missing XML driver implementation.

[2.0] Refined implementation and semantics of the merge and detach operations. General cleanups and API improvements. Added a testcase for detaching/serializing->unserializing->modifying->merging to demonstrate the transparent serialization.