public InventoryItem()
 {
     quantity = 0;
     itemObj  = null;
 }
 public InventoryItem(ItemObject item)
 {
     quantity = item.stackable ? 1 : -1;
     itemObj  = item;
 }
 public InventoryItem(ItemObject item, int quantity)
 {
     this.quantity = quantity;
     this.itemObj  = item;
 }