Added a create_window method to the Base widget which wraps the CreateWindowExW win32api call and allows classes to easily define what types of widgets they create, and the default styles they accept. This also entailed moving some of the Button class.
Use new widget infrastructure for the button class
Added basics of the label widget using the win32 static class
Added infrastructure to allow different parts of the app to register their own handlers for window messages.
Fixed debug print in libs/debug.py to use new-style print function
Enabled tab navigation in the main window and not just in dialogs, using example code from http://blogs.msdn.com/b/oldnewthing/archive/2003/10/21/55384.aspx
Added the beginnings of the TextInput widget using the new widget infrastructure. It does not yet support placeholders