Added support for OSG on Mac platform

models/cessna.osg

qgroundcontrol.pri

qgroundcontrol.pro

src/input/Freenect.cc

src/input/Freenect.h

src/ui/MainWindow.cc

src/ui/MainWindow.h

src/ui/MainWindow.ui

src/ui/map3D/GCManipulator.cc

src/ui/map3D/ImageWindowGeode.cc

src/ui/map3D/ImageWindowGeode.h

src/ui/map3D/Imagery.cc

src/ui/map3D/Imagery.h

src/ui/map3D/Pixhawk3DWidget.cc

src/ui/map3D/Pixhawk3DWidget.h

src/ui/map3D/PixhawkCheetahGeode.cc

src/ui/map3D/Q3DWidget.cc

src/ui/map3D/Q3DWidget.h

src/ui/map3D/Q3DWidgetFactory.cc

src/ui/map3D/Q3DWidgetFactory.h