Probably no more PyGTK Book Updates

I have decided to stop working on my pygtk book. I have moved it to https://github.com/majorsilence/pygtknotebook as that will make it easy for other people to continue working on it if they want. It covers pygtk 2.* and has nothing for the new pygtk 3.* or whatever it is now called.

If anyone wants to work on it they can fork it and send push requests with their changes.