Abbreviated site symmetry groups in bandreps

[thchr]

The site symmetry group labels are abbreviated in the 3D listings returned by bandreps (because they are abbreviated in Bilbao's BANDREP program). As an example, in e.g. space group 163, we have site symmetry groups "32" - but what we'd like to have are the labels of site symmetry groups we use elsewhere (e.g., "321" or "312").

The issue with not having having this abbreviated is that we cannot e.g. pass the site symmetry group label to the IUC2SCHOENFLIES dictionary which expects the full IUC labels and not abbreviated ones.

We can't just fix these by just replacing "32" by "321" because it could just as well be "312". Instead, we should just search for what the actual Wyckoff positions site symmetry group is and then replace it accordingly.

Longer term, the BandRep struct should probably just embed a SiteGroup instead of having the wyck and sitesym fields...

[thchr]

Steps have been taken towards improving this with calc_bandreps now returning a NewBandRep that contains all the above info and is better structured than BandRep. Still need to transition to this fully, longer term.