This patch is a (working) attempt to manage multi-db schemas.

I have successfully tested it on the reviewboard schema (from version 1.0.4 to 1.5).

To use it, just do as you would have used syncdb:

./manage.py evolve --database my_db

If you have any comments, don't hesitate.

A new test named multi_db has been created, but for obscure reasons, it doesn't work properly. All other tests passed. If you have any idea...