Staff activity v1.9 changes: Fixed null condition error.
Staff activity v1.8 changes: Fixed issue with moderated content count.
Staff activity v1.6 changes: Updated setup to use schema manager.
Staff activity v1.5 changes: Fixed issue with User group selection in the Options page. A server error was issued if there wasn't any User group selection in the Options page.
Staff activity v1.4 changes: Updated for XF v2.1 or newer. Also improved Options page to allow selecting User groups from a menu.
