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/structures/crates_lockers/crates.dm

@@ -211,10 +211,10 @@
 /obj/structure/closet/crate/secure/New()
 	..()
 	if(locked)
-		overlays = null
+		overlays.Cut()
 		overlays += redlight
 	else
-		overlays = null
+		overlays.Cut()
 		overlays += greenlight
 
 /obj/structure/closet/crate/rcd/New()
@@ -287,7 +287,7 @@
 		if (allowed(user))
 			user << "<span class='notice'>You unlock [src].</span>"
 			src.locked = 0
-			overlays = null
+			overlays.Cut()
 			overlays += greenlight
 			return
 		else
@@ -300,11 +300,11 @@
 	if(istype(W, /obj/item/weapon/card) && src.allowed(user) && !locked && !opened && !broken)
 		user << "<span class='notice'>You lock \the [src].</span>"
 		src.locked = 1
-		overlays = null
+		overlays.Cut()
 		overlays += redlight
 		return
 	else if ( (istype(W, /obj/item/weapon/card/emag)||istype(W, /obj/item/weapon/melee/energy/blade)) && locked &&!broken)
-		overlays = null
+		overlays.Cut()
 		overlays += emag
 		overlays += sparks
 		spawn(6) overlays -= sparks //Tried lots of stuff but nothing works right. so i have to use this *sadface*
@@ -357,10 +357,10 @@
 	if(!broken && !opened  && prob(50/severity))
 		if(!locked)
 			src.locked = 1
-			overlays = null
+			overlays.Cut()
 			overlays += redlight
 		else
-			overlays = null
+			overlays.Cut()
 			overlays += emag
 			overlays += sparks
 			spawn(6) overlays -= sparks //Tried lots of stuff but nothing works right. so i have to use this *sadface*