Some fixes for Python Game Programming section

I did some editing to the Python Game Programming section of the book. Fixing some links, and re-writing a few parts, and filling in missing bits. Thanks to Jonas for the support and feedback! There's a new 4000.zip up there now. If anyone else has any suggestions, please send them to rene@pygame.org.

I've started writing a section on rhythm games. Games where timing is important. These include dance games, and musical games. Did you know you can buy $5 dance mats off ebay/interwebs that pygame can use? This section will be a mini game showing the basics of how a rhythm game is made.

In pygame land, I've been researching how to do multiple language documentation. A student wants contribute a tutorial written in Korean, however we don't really have good support for non-english languages at the moment. Even though there are many tutorials written in other languages, we don't have support in our documentation tool for them.

Otherwise I've been reviewing a lot of code, and testing it before it goes into pygame. I really want to focus on fixing critical blocking issues for pygame 2, so soon I'm going to ask about implementing a policy of nothing-except-critical-fixes for the next couple of months. Additionally, focusing on one issue at a time, and working on it until it is done. It's not really how things are usually done in community projects where people work on whatever they like, and whatever interests them. This is usually great, except with such limited resources, it takes focus away from what is stopping us from releasing pygame 2. So this will be a little social experiment as well. Hopefully starting next week.