start sorting out the other rotations

done:
- feet
- thighs
- pelvis

working on it:
- shoulder

still to go:
- hands
shoulders rotation done (i think)

todo:
- hands
- humeral head
humorous rotating

i didn't know about surf2patch!!
this makes my life much easier
(and would have, previously…)
a bit messy but hands now rotate correctly
tidy up the calculation of global rotations
finally rename some structure fields sensibly