Preparation for refactoring into mutable and immutable WB_Point and
WB_Vector
Made WB_Point inherit WB_Vector.
WB_Vector and WB_Point x,y,z coordinates are no longer public. Access
through the WB_Coordinate interface.
Removed the old WB_Triangulate2D code. All triangulation now happens in
WB_Triangulate.
Removed several unneeded WB_*Indexed classes.
Made WB_Vector an extension of WB_AbstractVector class to enforce
encapsulation of x,y,z.