- Added new argument ``mssql_drop_foreign_key`` to
:meth:`.Operations.drop_column`.  Like ``mssql_drop_default``
and ``mssql_drop_check``, will do an inline lookup for a
single foreign key which applies to this column, and drop it.
For a column with more than one FK, you'd still need to explicitly
use :meth:`.Operations.drop_constraint` given the name,
even though only MSSQL has this limitation in the first place.
- Fixed an issue with unique constraint autogenerate detection where
a named ``UniqueConstraint`` on both sides with column changes would
render with the "add" operation before the "drop", requiring the
user to reverse the order manually.
- reorganize the index/unique autogenerate test into individual test cases;
ideally the whole test suite would be broken out like this for those big
tests