It's possible to rotate the artboard, but the objects are still on their old positions.
I found the is a button to bind artboard and objects for MOVING the artboard together. Why does that not work for rotation?

In the mean time I have written a small JavaScript to solve this: https://www.behance.net/gallery/125369255/Javascript-for-Illustrator-RotateArtboard

I hope, we can use a rotation of an artboard with it's objects soon in AI.
– Jens.