Avalonia updates

[jpobst]

These updates have the following issues:

• Repaints on Mac do not work. The initial screen will be drawn correctly, but is never invalidated and redrawn.
• Need to add AddService<IKeyboardDevice>(new KeyboardDevice()); to AvaloniaGlobals.InitializeOSX.

I cannot figure out how to fix the repaints, so for now I'm going to just ship all the updates until that point.