Added a Python player!

It crashes half the time because GObject Introspection isn't actually
officially supported with GTK 2. However, it's a simple player that
shows how to use Chimara in Python. We don't even have to write any
language bindings, thanks to the power of GObject Introspection! But
if we want to do anything serious with Python, we will need to port to
GTK 3 first.

It's a straight port of the C player, but it's 300 lines instead
of 1200 ;-)