Code challenge ready for pull

Completed the code challenge in Python with the Tkinter library as a desktop GUI app. See the "README.txt" for how to run it (you may need to install python-tk ). It weighs in at 206 lines, and I have yet to be able to beat the computer. It took about 2.5 hours from start to finish, not counting interruptions (family, work, etc). The code could be cleaned up a little bit, but I'm reasonably happy with it.