Filled out more of the gtk.Window utility functions

I added a bunch of functions for gtk.Window, trying to follow your structure.  Feel free to critique and give me feedback.

I added TODO's where functions are not implemented in the hopes that I or someone can come back through and add them in the future.

I'm just doing this in my spare time.  I would like to create some examples/tests, and maybe continue on to some of the other structs when I can.