EMPTY                   Constant for the empty square. It's value is
                        the character "_".
NONE                    Constant for no winner. It's value is the
                        character "_".
O                       Constant for the O player.
X                       Constant for the X player.
firstAvailableMovePlayer
                        Player that always takes the first move in the
                        list of valid moves.
gameState               The game state is represented by a list of 8
                        values.
getMoves                Get the list of valid move from the game state.
makeMove                Apply the move to the current game state an
                        produce a new game state.
playGame                Play a game of Tic-Tac-Toe using the two
                        provided stragies.
randomMovePlayer        Player that picks a random move
rt3                     rt3: A Package for Playing Tic-Tac-Toe in R.
startGame               Start a new game
