Add a way to move rapidly the camera above robot

[adegroote]

In large scene, it is a bit cumbersome to move manually the camera to see what each robot do. Having a way to do it automatically would be nice!

[PierrickKoch]

We can add a key, F8 ?, since F9 is used to switch camera.
The function would move CameraFP to ~robot.location.{x - 2, y, z + 1}.
It would be nice to finish #410 first.