New hud

Hi. 
This is draft of new HUD developed to be:
1) highly customizable (settings dialog from context menu)
2) able to use both soft and OpenGL rendering
3) has fps limiter to reduce power consumption
4) not replace current HUD, just add other (you can enable it using main QGC menu)

My own reason of new HUD developing is following. Netbook recently bought by me has piece of PoverVR crap instead of normal Intel GPU, so no hardware OpenGL support in it. It ha Mesa software emulation but it is painfully slow. On the other hand software 2d engine in Qt works surprisingly fast. So I go ahead and write my own. Next reason is Qt experience I want to obtain.

This is just preview. I will work on it more.