Microwaves now have a single wire (#41822)

cl coiax
add: Microwaves have a single wire accessible when open, the activation wire.
When cut, the microwave will no longer function, when pulsed, the microwave
will turn on.
add: Stabilized dark purple extracts now cook items in your hands, rather than dropping
the cooked item on the floor.
/cl

Previously microwaves just worked on their contents, now they keep a subset of contents called ingredients, because otherwise it would explode whenever you put a signaler inside.

Someone asked me to do it. It seemed like a neat idea. God knows
what horrible things people will do with this.

code/game/objects/items/stacks/stack.dm

@@ -396,7 +396,7 @@
 	//TODO bloody overlay
 
 /obj/item/stack/microwave_act(obj/machinery/microwave/M)
-	if(M && M.dirty < 100)
+	if(istype(M) && M.dirty < 100)
 		M.dirty += amount
 
 /*