Add Blaze's Turret mod

per http://smf.cataclysmdda.com/index.php?topic=8060.msg190017#msg190017

This is the Vehicle Turret Mod, by Blaze. I have not done any work on this other than submitting it here, so all credit goes to Blaze.
OK, so it's indeed a metal-tipped wooden bolt.  (Syntax up there too, but we can fix that.)