Created by: portnov
This adds a few nodes to "manually" manipulate knots of NURBS curves and surfaces:
- Curve category:
- Insert Knot
 - Remove Knot
 - Remove Excessive Knots
 
 - Surface category:
- Insert Knot
 - Remove Knot
 - Remove Excessive Knots
 
 
Preflight checklist
Put an x letter in each brackets when you're done this item:
- 
Code changes complete.  - 
Code documentation complete.  - 
Documentation for users complete (or not required, if user never sees these changes).  - 
Manual testing done.  - 
Unit-tests implemented.  - 
Ready for merge.  
