Presenter & View
1. Made some improvements to the user interface by adding more images 
for the display of the board and the current player. And added a stylish
button for passing and restarting the game
2. Added extensive comments to the presenter and view classes
3. Fixing some bugs relating to the history support of the game.

Model:
Extract some methods from the State class to the Judge class, now the
judge object is responsible for validate moves and remove stones from
the board. Changed the javadoc accordingly