New Version of the Typing Game

I added a bunch of little enhancements, including an introduction and an option to play again. Also, I made the main loop a function. This will help in future enhancements to the game and for testing purposes. 

easygui is now a prereq for the game. 

Also, as simple as the game is to figure out, I think in the future there needs to be a set of instructions. Just add a button to the intro box for that.