Ports in microwave updates and its radial menu.

code/game/objects/items.dm

@@ -686,7 +686,7 @@ GLOBAL_VAR_INIT(rpg_loot_items, FALSE)
 		..()
 
 /obj/item/proc/microwave_act(obj/machinery/microwave/M)
-	if(M && M.dirty < 100)
+	if(istype(M) && M.dirty < 100)
 		M.dirty++
 
 /obj/item/proc/on_mob_death(mob/living/L, gibbed)

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
 
 /*