Tried to generalize booleans in Diagrams.TwoD.Arc and Diagrams.TwoD.Ellipse as good as possible.

'Diagrams.TwoD.Arc.bezierFromSweep' returns a list of segments. That can not be generalized properly up to now.
'Diagrams.Path.Trail' may need a generalization to 'BooleanOf v' because of its use in 'Diagrams.TwoD.Arc.arcT'