Multiple user delete added

It's been a long time coming but we have now added a multiple user delete function to the "View users" page.
This should prove useful for deleting departed students from the database. Remember the data protection act says you should only keep data as long as is necessary.
NOTE: You may not be able to delete huge numbers of users at a time as our servers may time out, you may have to try deleting 10-20 at a time.