README updates and proposed way to do 'tutorials'

Hi Zach.
I've updated the README.md to link to the examples.
I was wondering... do we really *need* tutorials for the example files? How about if I just comment the example files so that people can download them and then read through? The way I'd envisaged the 'tutorial' md files was basically to get the code and explain it as you read it... So, really, commented code would be exactly the same but without additional .md files to have to take care of.
I've done the button.py file in the way I'm suggesting, so please take a look and let me know what you think.

Mike