Cleaned up and commented major code parts. Refactoring HDD and HSI widgets to support QGraphicsView drag-and-drop, tested multi-MAV support more intensely, currently adding the system coloring to all widgets

Major refactoring of the waypoint code. The new design fits the model-view-controller pattern better.

UASWaypointManager now implements the protocol described in http://qgroundcontrol.org/waypoint_protocol