ImageOverlayManager: Address comments from #212, clean up aspect ratio
ImageOverlayManager: Address comments from #212, clean up aspect ratio

mitdrc/director,manuelli/director,openhumanoids/director,RobotLocomotion/director,manuelli/director,patmarion/director,openhumanoids/director,RobotLocomotion/director,mitdrc/director,patmarion/director,RobotLocomotion/director,patmarion/director,mitdrc/director,manuelli/director,mitdrc/director,RobotLocomotion/director,openhumanoids/director,openhumanoids/director,manuelli/director,openhumanoids/director,manuelli/director,RobotLocomotion/director,patmarion/director,patmarion/director,mitdrc/director