Merged requested to merge fix/error-message-gridgeometry-parallel-box into master
The error in box signifying that box does only work in parallel with zero overlap was accidentally commented in c5787288 and slipped the review.
This adds it back in (only concerned caching=false).
This also adds an error message for the parallel periodic boundaries with box which is currently not implemented.
Should be backported to 3.1.
Fixes #786 (closed)