Allow screen rotation on ground station

[steveatinfincia]

The Pi is not capable of rotating the screen using accelerated hardware (it has to be done by the firmware on the GPU), as a result when people try to use display_rotate in config.txt the Pi can't keep up and huge latency is the result.

Instead we'll have to rotate while rendering in QOpenHD which should work fine, but will require pulling the video rendering into QOpenHD itself instead of using hello_video.