Split a knot vector at the center, by adding multiplicity k knots near the middle of the parameter range. Tries to start with an existing knot, but will add a new knot value if there's nothing in "the middle" (e.g. a Bezier curve).

'Declaration
 
Public Overloads Shared Function Split( _
   ByVal U() As Double, _
   ByVal m As Integer, _
   ByVal k As Integer, _
   ByRef splitPt As Integer, _
   ByRef midVal As Double _
) As Integer

public static int Split( 
   double[] U,
   int m,
   int k,
   out int splitPt,
   out double midVal
)