NURBS funcional classes

[AlanRynne]

There are currently only some methods created following the instructions on The Nurbs Book.

Implementation must be finished and refactored into classes. Initially, at least they will be:

• NurbsSurface.cs
• NurbsCurve.cs
• Brep.cs

[github-actions]

This is your first issue! Thanks for taking the time to do this!!