Fix constructor of struct tsDeBoorNet in case of deg <= 1.
Fix constructor of struct tsDeBoorNet in case of deg <= 1.

retuxx/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline,retuxx/tinyspline,retuxx/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline