Start the game.

        The value of option 'pregame' determines whether the pregame will occur or not.

        - Resets the board
        - Sets the players
        - Sets the game state to the appropriate first turn of the game
        - Finds the robber on the board, sets the robber_tile appropriately
        - Logs the catanlog header

        :param players: players to start the game with

def start(self, players):
        """
        Start the game.

        The value of option 'pregame' determines whether the pregame will occur or not.

        - Resets the board
        - Sets the players
        - Sets the game state to the appropriate first turn of the game
        - Finds the robber on the board, sets the robber_tile appropriately
        - Logs the catanlog header

        :param players: players to start the game with
        """
        from .boardbuilder import Opt
        self.reset()
        if self.board.opts.get('players') == Opt.debug:
            players = Game.get_debug_players()
        self.set_players(players)
        if self.options.get('pregame') is None or self.options.get('pregame') == 'on':
            logging.debug('Entering pregame, game options={}'.format(self.options))
            self.set_state(catan.states.GameStatePreGamePlacingPiece(self, catan.pieces.PieceType.settlement))
        elif self.options.get('pregame') == 'off':
            logging.debug('Skipping pregame, game options={}'.format(self.options))
            self.set_state(catan.states.GameStateBeginTurn(self))

        terrain = list()
        numbers = list()
        for tile in self.board.tiles:
            terrain.append(tile.terrain)
            numbers.append(tile.number)

        for (_, coord), piece in self.board.pieces.items():
            if piece.type == catan.pieces.PieceType.robber:
                self.robber_tile = hexgrid.tile_id_from_coord(coord)
                logging.debug('Found robber at coord={}, set robber_tile={}'.format(coord, self.robber_tile))

        self.catanlog.log_game_start(self.players, terrain, numbers, self.board.ports)
        self.notify_observers()