Taxonomy Context Uninstall

The Taxonomy Context module didn't previously implement an uninstall hook. Attached is a patch that adds the hook to remove the appropriate tables and variables from the database.

So far I have only tested with MySQL (5.0), but I am confident it should work across the board, however. Considering the patch has "DELETE" in it, I would prefer to get at least a second set of eyes to review the code before committing it.