Add GNU 30 year animation code.

  This contains a *very* basic GIF reader and display-er. This code can
  be cleaned up a bit. Some known bugs:

    - Gifs bigger than the size of the building will only be sampled
      from 0,0 -> height,width of the building.

    - Gif frame-delays are ignored for a static speed. This is perhaps
      not great.

    - The code to set / manage gifs is a bit sloppy. It should work
      fine, but it may need a tweak if we're going to show the code off.