Update to list based lookup

src/engine/gameManager/BuildingManager.java

@@ -53,8 +53,14 @@ public enum BuildingManager {
 
         int numOfSlots = _slotLocations.get(building.meshUUID).size();
 
+        if (building.hirelings.isEmpty())
+            return 0;
+
         for (int i = 0; i < numOfSlots; i++) {
 
+            if (i > building.hirelings.size())
+                return i;
+
             if (building.hirelings.get(i) == null)
                 return i;
         }
@@ -73,8 +79,14 @@ public enum BuildingManager {
 
         int numOfSlots = _slotLocations.get(building.meshUUID).size();
 
+        if (building.hirelings.isEmpty())
+            return numOfSlots - 1;
+
         for (int i = numOfSlots - 1; i >= 0; i--) {
 
+            if (i > building.hirelings.size())
+                return i;
+
             if (building.hirelings.get(i) == null)
                 return i;
         }