Slot tracking update

src/engine/gameManager/ForgeManager.java

@@ -185,7 +185,7 @@ public enum ForgeManager implements Runnable {
         // Subtract slots currently being used by npc workOrders
 
         for (WorkOrder npcWorkOrder : ForgeManager.vendorWorkOrderLookup.get(workOrder.vendor))
-            availableSlots = availableSlots - npcWorkOrder.slots_used;
+            availableSlots = availableSlots - npcWorkOrder.cooking.size();
 
         // Single item rolls are always a single slot