S4u.sqlalchemy

-----------------------

- Modify upgrade content provider to always mark the transaction as changed so
DDL is flushed in a commit. Again - this change got lost somewhere.

-----------------------

- Do not create multiple engines when our upgrade context provider is used
multiple times.

-----------------------

- Modify upgrade content provider to always mark the transaction as
changed so DDL is flushed in a commit.
[wichert]

- Make database URL used in DatabaseTestCase configurable via a new
``db_uri`` class variable.
[wichert]

- Abort transaction earlier during test breakdown so we do not try to
drop tables while another connection is open within a transaction.
[wichert]

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- Update alembic 0.2.0 release which changed its API especially for us.
[wichert]

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- Update DatabaseTestCase to abort any open transaction. This clears out all
open SQL connections.
[wichert]

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- Setup an `alembic <http://pypi.python.org/pypi/alembic>`_ context
as part of the upgrade context.
[wichert]