Link orientation of reciprocal and real space

[giovannipizzi]

While real and reciprocal lattices are, of course, different, orientation in real and reciprocal space has the same meaning.

Finding a way to indicate the correspondence between real-space and reciprocal-space directions can be very helpful for linking properties like dispersion of bands, etc. to the crystal structure.

In the seekpath output you show both real and reciprocal space side by side, and you could couple the two orientations together (so that, if you rotate one, the other rotates accordingly).

Moved from giovannipizzi/seekpath#46