Update orientation viewer

[pkienzle]

Address various issues in the orientation viewer that have crept in over time.

• Δφ rendering bug: did some lint cleanup but didn't test the consequences (6 years ago!)
• fix zdir issue with newer matplotlib
• calculator no longer ignores unused parameter psi, dpsi, etc. for cylinder model, so don't pass it in
• add labels to axes so we can see the orientation of the detector
• warn user of potential issue with fcc/bcc models: we resolved the discrepancy between docs and code regarding nearest neighbour distance in the paracrystalline models, but I haven't checked whether the orientation viewer is consistent.
• fix typo in explore/angles.py. That code will be used again when we start to model data with qz, and need to update our rotation matrices.

The orientation viewer is no longer used by SasView.

Fixes #669.

[krzywon]

Seems reasonable