Take advantage of openGL hardware graphics acceleration

[Maker42]

To do this, we need to use "QOpenGLWidget" instead of QWidget.

And for QGraphicsView, we should:

myGraphicsView->setViewport(new QGLWidget());

(Or the PyQt equivalent)

[Maker42]

The use of openGL appears to be quite temperamental, and doesn't work on systems without the right driver versions.
This should be at most a configuration item rather than intractable in code.