Too remove potential excessive garbage collection per tick. We will be reusing lists for overlays instead of deleting and creating them.

the .Cut() proc on a list will empty a list by default. This also will set the len to 0.

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@5465 316c924e-a436-60f5-8080-3fe189b3f50e

code/game/objects/items/shooting_range.dm

@@ -36,7 +36,7 @@
 		if (istype(W, /obj/item/weapon/weldingtool))
 			var/obj/item/weapon/weldingtool/WT = W
 			if(WT.remove_fuel(0, user))
-				overlays = null
+				overlays.Cut()
 				usr << "You slice off [src]'s uneven chunks of aluminum and scorch marks."
 				return