Don't stop automatic rotation when rotating Preview3D

[vreon]

This has come up on Discord a couple of times (1, 2) and I happened to have a local patch for this already :smile:

[bliepp]

Actually, I think it is a good thing that autorotation stops. When navigating the 3D preview one is usually aiming for a specific perspective. If the rotation didn't stop the preview would continuously change which is not what one would expect when explicitly navigating the camera to a different position.

I would suggest an option to toggle your desired behaviour on explicitly instead of making it the default as the current default is the most intuitive in my eyes.

[vreon]

Closing in favor of #534.