Added a failing test for the score penalty feature
Added toString for Computer and Human (for easier-to-read logs)
Implemented the -2 penalty when a player can't move.
Wrote a failing test for "Change so that one cannot swap diagonally."
Implemented "Change so that one cannot swap diagonally"
Added failing test for "Change so that if a node is at the boundary the
score will be double from that node."
Refactored: NodeImpl now uses NodeObserver instead of Observer
Implemented "Change so that if a node is at the boundary the score will
be double from that node."