Get rid of redundant rect draw
Partial implementation of drawing video via UAV::Pilot::SDL::Window.  API implemented, but video is blank.
Fix video output
Add API change for next version
Generalize some of WindowEventHandler's functions.  Stub test for UAV::Pilot::SDL::Window.
Add tests (and some supporting methods) for UAV::Pilot::SDL::Window.  Add .c files to gitignore.
Add a single child
Can add multiple children to window and float them top and bottom
ARDrone uav lib always puts video on top, nav on bottom