The blockers are in the EP brake of a vehicle, older than this work: its
arrays made with new[] are vectors now, which also removes the deletes.
- The caches of the unevenness of a track are no longer mutable: what fills
them isn't const any more.
- TSegment gets back to RaPositionGet in one piece, with what the path has
to do with the others in one struct.
- Less nesting in the group of switches and in the fields of the editor,
nested conditionals written out, and the attribute is read from a
string_view. A test no longer counts in floating point.
No change in behaviour.