GUI samples with configurable target frame rate

[IngmarBitter]

[Idea] Add to the GUI samples (WinForms and similar) a timer to implement rendering at a configurable target frame rate. By default the frame rate should be 60Hz. This implies that something in the rendering must change every frame to demonstrate that we are rendering at that rate.

However, mouse interaction should also result in a visible change of the rendering. Both can be done by updating different rendering parameters. The render timer can change the colors of the shape, and the mouse interaction can change the position or orientation.