IMPORTANT: the harmony example has been removed. If anybody is willing to
invest the required time: go for it...

In case of OST, the GL context is typically under control of QT. QT makes
sure that the right context is active in InitGL(), RenderGL() etc. However,
this is not guaranteed when calling gl related functions on other occasions.

What is NOT done yet:
- OpenGL context of QOpenGLWindow must be made
  active before calling any GL function in scene.cc. The wrong
  GL context is active otherwise.
- cmake polishing
- final grepping for QT4 leftovers

solves a variety of problems that gcc (mainly the c++11 as default)
throws at us.