Changes:
-Rewrite StockTankDisplay.java to allow the object to be display. At this moment, there isn't a method in PipeToGUI to send the fish object to GUI for display.
-Rewrite EditMenu.java to display the object's attributes when user clicks on the object inside Arena Tank.

Known Issues: 
-JSONObject for fish attribute should have a key called "Tank". We can use this key to mark the fish if they are in Arena, Stock, or Isolation tank. So that when a fish is marked "Stock Tank" it shouldn't be display in Arena Tank.
-When trying to remove an Object from Stock Tank display Panel, system prints "Could not remove object with ID..." 

Note: In the AddObject Menu, there is a radio button to specify where the user wants the fish object to be. ex: Arena tank or Stock Tank. If Stock Tank is selected, Game World should return the object attribute back to GUI for display.