minor touch up changes
removed the game object as a parameter that needed to be passed in to all calls to chess piece objects
getPossibleMoves and related methods are now returning lists instead of arraylists for better abstraction
removed subclass implementations of canReach and canDefend because they were the same for all of them
refactored getPossibleMoves and getDefenseMoves to be more concise
completed first draft of junit test for castle. still needs stuff for castling
cleaned up Location.java class
added a second move method for the chess board class that does not use a move object.
added static imports for Occupier enum in chess piece classes
WIP: initial work on HorseTest.java