[nek refine] rotation

[yslan]

There seems to be an inconsistency in the element rotation.
It works fine if elements are in position 5 (no rotation) or 6 (flip t axis).

Fixing is easy, but it needs a clean and clever tests.

Due to the symmetry, for most meshing actions, the geometry is likely to be the same.
However, this might mess up the boundary conditions.