Merge awernerdlr's B-spline constraints.
constraint-b-spline: astyle + indent.
constrained-b-spline: refactoring, cleaning.
constrained-b-spline: improve test.
constrained-b-spline: add size check on parameters in test.
constrained-b-spline: fix coupled constraint.
constrained-b-spline: fix Gnuplot x range.
constrained-b-spline: fix checks after last change in test.
Merge pull request #14 from bchretien/constrained-b-spline

Constrained B-spline