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/modules/assembly/holder.dm

@@ -60,7 +60,7 @@
 
 
 	update_icon()
-		overlays = null
+		overlays.Cut()
 		if(a_left)
 			overlays += "[a_left.icon_state]_left"
 			for(var/O in a_left.attached_overlays)

code/modules/assembly/infrared.dm

@@ -39,7 +39,7 @@
 
 
 	update_icon()
-		overlays = null
+		overlays.Cut()
 		attached_overlays = list()
 		if(on)
 			overlays += "infrared_on"

code/modules/assembly/proximity.dm

@@ -78,7 +78,7 @@
 
 
 	update_icon()
-		overlays = null
+		overlays.Cut()
 		attached_overlays = list()
 		if(timing)
 			overlays += "prox_timing"

code/modules/assembly/timer.dm

@@ -55,7 +55,7 @@
 
 
 	update_icon()
-		overlays = null
+		overlays.Cut()
 		attached_overlays = list()
 		if(timing)
 			overlays += "timer_timing"