- Added :paramref:`~.Operations.batch_alter_table.naming_convention`
argument to :meth:`.Operations.batch_alter_table`, as this is necessary
in order to drop foreign key constraints; these are often unnamed
on the target database, and in the case that they are named, SQLAlchemy
is as of the 0.9 series not including these names yet.
- rework the docs on batch + constraints, which remains subject
to a lot of caveats and problems, some to be resolved in SQLAlchemy 1.0