added gui JTextFields and JButtons as member variables, for easy access
fixed bug where board was 1 indexed instead of zero indexed, add some skeleton code for action listeners
actionLister for 'Next Player' button successfully changes activePlayer to next player and rerolls the die. However, it does not yet check if the current player has moved
added skeleton code listeners for the board (as mouse listeners) and the 'Make an Accusation' button