Gui: Cleanup Qt OpenGL usings in QtOpenGL.h.

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.

src/Gui/ManualAlignment.cpp

@@ -352,7 +352,7 @@ public:
         bool smoothing = false;
         bool glformat = false;
         int samples = View3DInventorViewer::getNumSamples();
-        QtGLFormat f;
+        QSurfaceFormat f;
 
         if (samples > 1) {
             glformat = true;