Module 6 completed and passed off yesterday, working on module 7

ANOTHER LIST OF CHANGES
-Added ChessGameWindow and a gui package to prepare for module 8
-Fixed up imports in GameManager and moved friendly pieces ArrayList out of scope slightly
-Location 'toString' fixed, I was accidentally incrementing columns and messing everything up
-Got rid of unnecessary commented out code in Chessboard
-Player now has a method to determine a piece's type, and the 'takeTurn' method now works properly and prints out all possible moves
-All pieces now have a copy constructor