Usage of ./tictactoe:
  -a	show computer analysis (default true)
  -c	computer starts (default true)
  -d int
    	AI depth (-1 for best play) (default 5)
  -l	show one board at a time (clear screen) (default true)
  -n int
    	number of players (default 1)
  -s duration
    	simulate thinking by "sleeping" (default 500ms)