An amazing tic tac toe game.

I made this to play around with Tkinter GUIs, which is not that fun. I also practiced using pytest for the first time. Cool.

Run ttt_ui.py then click on buttons to try to beat the randomly-playing computer! You can always restart by clicking "New Game". Yaaaaaay!

Run py.test from project root directory. It is assumed that the tittertactoe package is "importable" in the current virtual environment (i.e. pip install -e . in project root) as per these guidelines: https://pytest.org/latest/goodpractises.html#choosing-a-test-layout-import-rules