"Professional CMake" book suggest the following:
"Targets should build successfully with or without compiler support for precompiled headers. It
should be considered an optimization, not a requirement. In particular, do not explicitly include a
precompile header (e.g. stdafx.h) in the source code, let CMake force-include an automatically
generated precompile header on the compiler command line instead. This is more portable across
the major compilers and is likely to be easier to maintain. It will also avoid warnings being
generated from certain code checking tools like iwyu (include what you use)."
Therefore, removed the "#include <PreCompiled.h>" from sources, also
there is no need for the "#ifdef _PreComp_" anymore
Previously the code defined compatiblity usings in `QtOpenGL.h` header,
which I think was added for backwards compatiblity with previous Qt
OpenGL widgets.
As far as I can tell, this is not necessary anymore, and can be cleaned
up.
Quarter Widget soes not allow to switch of multisampling on the fly, therefore we need to use glgraphicsitem instead of direct opengl xor rendering for mouse selection
-removes all soqtviewer references
-create a quarter adaptor class which implements missing functionality
-adopts freecad code to make use of SoRenderManager and changed View3DInventorViewer interface
