coordinate system cleanup

- coordinateSystem, cylindricalCS, sphericalCS:
  get copy with name constructor

- cylindricalCS, sphericalCS:
  can switch off default degrees

- dropped cartesianCS class (already covered by coordinateSystem) and just
  always use coordinateSystem directly.
  The dictionary runtime selection still accepts type "cartesian" as an alias,
  to provide the least surprises.

- dropped runtime selection based on origin/axis/direction (not used), but
  left runtime selection based on origin/coordinateRotation as still being
  potentially useful.