Curve decimate, since we have curve fitting calculation,
its not so much extra work to support decimating.
This patch also has an option for freehand drawing.
This generally works, but theres some todo's still.
Todo:
- Option to keep 'free' knots (don't remove corners).
- Option to decimate based on error threshold (currently is a factor of the number of points per nurbs curve).
- Possibly use this for FCurves too.