Quaternion.to_vector() protocol missing key specifications

Every quaternion protocol is different, specifically, the following options should be specified for every quaternion representation of rotation:

- chirality: should be left-handed or right-handed
- coordinate system: should be ijkw, wijk, or some esoteric coordinate system
- marshalling sequence: should be ascending or descending
- normalisation: should be normalised or unnormalised

from documentation I was able to piece out a few options:

- coordinate system: ikjw on to_vector(), wijk on construction
- normalisation: unnormalised unless it is UnitQuaternion

the other 2 specifications are still missing, specifically, the entire source code file doesn't mention "chiral" or "hand" anywhere.

Can we add them?