Update to single item rolling config

src/engine/gameManager/ForgeManager.java

@@ -124,6 +124,13 @@ public enum ForgeManager implements Runnable {
             workOrder.slots_used = calcAvailableSlots(workOrder);
 
             workOrder.total_produced = 0;
+
+            // Single item configuration
+
+            if (workOrder.multiple_slot_request == false &&
+                    workOrder.total_to_produce == 0)
+                workOrder.total_to_produce = 1;
+
             workOrder.total_to_produce *= workOrder.slots_used;
             workOrder.production_cost = calcProductionCost(workOrder);