Based on OpenSceneGraph-3.4.0 (f4013a68daeeb00cee29e36d427ef2d9ec7a3ff1)

Renamed the directory, namespace, etc to not cause clashes with the
actual osgqt.

Note: This copy of osgQt is part of OpenModelica because distributions
ship with osg compiled against Qt4, whereas OMEdit uses Qt5 when
available.
