DO NOT MERGE because not complete: not all constraints are not transferred.
Includes:
* Adjust `deriveConstraintsForPieces` for trim
* Make sure new points are constrained on the cutting edges
* Add constraints at trim end(s) dependent on pre-exisiting ones with cutting curve(s). Also change tests to reflect that auto-coincidence can now be applied to non-periodic curves as well.
Known issue(s):
* Some redundant constraints may be added under certain circumstances (e.g. in
presence of perpendicular-via-point)
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