Legend added

So the legend is added. Here's the tip on how to do more with this:

1. To add more people (i.e. make the gif longer), you need to modify the bs-algo.py file to add more people. Ask me (afding@gmail.com, 419-283-1344) or Matt Shanahan for more info.
2. animation.gif was created with the following command (in the directory containing the gs_pic files):

$ convert delay -200 -loop 0 gs_pic*.png animation.gif

Note that this requires the gs_pic*.png files to be in the correct order (000 goes first, 001 goes second, etc.)