2020年9月 修改了少量代码以适应 python383: 主要是print函数加（）及 Tkinter-> tkinter 两类修改 by liujianhua
To run
python ChessGame.py
TODO Add an AI engine. The engine should accept a board. And and return move (x,y,dx,dy)
get_moves_for_board(board, is_red) return a list of (x,y,dx,dy)
unmove()
alpha-beta