Initial commit.
Initialized tic_tac_toe module.
Started game structure.  Created basic tests.
Added some error checking for Board.move().
Added Board.show() with tests.
Updated Board.show() to display position numbers.
Cleaned up type annotations.
Initial work on Program.  Updated Player and Game implementations and tests.
Added run script.
Added tests to run script.
Refactored Board and Game into single class.  Added get_*_spaces methods and tests.
Added test for player choice.
Added main() function for game module to normalize __main__ module.
Added get_winner() and tests.
Added Game.State and tests.  Replaced assertEqual with assertIs where applicable.
Initial minimax algorithm.  Added preliminary test.
Refactored board show to use format_board.
Added another test for minimax.
Fixed algorithm to pass test.
Added colorized mode.