slope function for high order curves
Skeletons for new classes, refactor pending

BezierComponent, Bezier, Polyline, Spline
generalized subdiv for more dimensions
implementation of Bezier and Polyline
implementation of Spline
implement of CurveTrace
tweaks and fixes
Test sample, further fixes
Feature refinement: FMB, TrackMatte, Binder.Link

TrackMatte now supports alpha mask, FMB now preserves blend mode better,
Binder.Link now evaluates linked property only once per frame
fixes blendmode bug
exe->rb, even better FMB blendmode fidelity
fixed FMB alpha edge situation