Improvement: add animated gifs to Day 5 #13

The Day 5 material is how to create animations in PyGame. It would be better if each challenge problem had a finished video (in the form of an embedded animated gif) to show the expected result.

Here is the format for embedding in markdown:
![alt text](http://www.gifanimations.com/thumbs/NjI1MWZjNWY0OGIzN2E=/NTJmYzVmNDhiMzdh/cartoon.jpg "Logo Title Text 1")

Initial research shows this might be a tool to help: http://www.cockos.com/licecap/