Chad Harter's submission for Tic-Tac-Toe

Thanks for the opportunity guys!  Hopefully it's an easy read.  I look forward to hearing from you!

This implementation doesn't require installation of any thirdparty libraries or anything like that. 

To play the game, just run:
```
$ python tictactoe.py
```

To run the unit tests, just run:
```
$ python -m unittest discover -v test
```