connect four player

so far, this has these classes:

class_board: represents the board. can identify winning runs, winning tokens.

class_player_basic: very naive. plays the first legal move.

class_player_thinking(class_player_basic): an "abstract" class, in that it's never direction instanciated. this is just here to provide a way to get the legal moves.

class_player_random(class_player_thinking): chooses a random legal move

class_player_winChooser(class_player_random): if there's a move that immediately wins, do that! otherwise, random.

class_player_winChooserLossAvoider(class_player_winChooser): if there's a move that immediately wins, do that! if there's a move that (could) lose next turn, don't do that ! otherwise, random.