Fixes stacks acting strange for cyborgs

Robot modules weren't handling qdel'd stacks properly, so now they
simply don't get qdel'd. They shouldn't get deleted often enough for
this to hurt performance.

Also, the module slot of a stack will now be deselected when it's used
up, and it will show up immediately when respawned while recharging.

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

@@ -142,11 +142,11 @@
 			new_item.amount = R.res_amount*multiplier
 			//new_item.add_to_stacks(usr)
 		src.amount-=R.req_amount*multiplier
-		if (src.amount<=0)
+		if (src.amount < 1) // Just in case a stack's amount ends up fractional somehow
 			var/oldsrc = src
 			src = null //dont kill proc after del()
 			usr.unEquip(oldsrc, 1)
-			del(oldsrc)
+			del(oldsrc) // Not qdel, because qdel'd stacks act strange for cyborgs
 			if (istype(O,/obj/item))
 				usr.put_in_hands(O)
 		O.add_fingerprint(usr)
@@ -165,10 +165,11 @@
 	if (amount < used)
 		return 0
 	amount -= used
-	if (amount <= 0)
+	if (amount < 1) // Just in case a stack's amount ends up fractional somehow
 		if(usr)
 			usr.unEquip(src, 1)
-		qdel(src)
+		spawn()
+			del(src) // Not qdel, because qdel'd stacks act strange for cyborgs
 	update_icon()
 	return 1