Oracle: add support for table and index compression and bitmap indexes
The 0.9 series made it a lot more difficult to create ad-hoc extensions to the existing dialects by disallowing parameters the core does not understand. We need a couple Oracle-specific features, so I spent some time generalizing them for inclusion in SQLAlchemy. I've tried to make the patch work for older Oracle releases too, but I have access to 11g only so I could not test anything older. I don't have DBA access either, so I was not able to run some of the tests that require extra privileges.