Simulate the game Gomoku on a board.

The default implement is in env.py.

The default board size is 15. The max support size is 64.

10000 games take about 8 seconds.

The average step is used to verify the environment, and the number is supposed to be about 109.

There is another implement in env_rec.py. I keep this here because I think the way to check if the game is end is interesting, and also it supports the board size larger than 64. But it is slower than env.py, about 16 seconds for 10000 games.

verify.py is used to verify the environment.