rename openTrail['] to mkOpenTrail['] to avoid confusion with closeTrail
D.Trail: new trailFromVertices function
some work on converting D.TwoD.Polygons
D.Trail: new trailFromOffsets function
work on converting D.TwoD.Polygons.polySidesTrail
convert D.TwoD.Shapes
convert D.Animation
convert D.TwoD.Segment
convert D.TwoD.Path (left Traced Trail instance as todo)
convert D.TwoD.Combinators
polyVertices is now polyTrail
pragma/import cleanup in D.TwoD