Fix for crash when removing item from QuickView, and addition of more generic signal/slot combonation for property updates

First stab at JSBSim interface, compiling, operational, but needs the correct startup folders and arguments

Implementation of 6DOF 3DMouse input (Windows only). Not tested yet.

Pushed HIL with X-plane to being close to operational. Receiving from X-Plane  implemented, sending to it is prepared. Needs an iteration of onboard SW first

Added a unit test, setAirframeTest. Changed setAirframe function. Added an end_of_enum to the airframe enum.

Added remote OpenGL drawing in 3D view. Any external application can draw to the 3D view via the protobuf implementation of GLOverlay messages.

Added multi-UAS support to QGCRGBDView. Fixed display timeout issue on computer for which data source is not time-synchronized.

Added visualization of obstacles. Fixed relative font path issue in 3D widgets by using QFont within osgText::Font instead of using static font filename.