Take curve out of hpp namespace

CMakeLists.txt

include/curve/CMakeLists.txt

include/curve/MathDefs.h

include/curve/bernstein.h

include/curve/bezier_curve.h

include/curve/bezier_polynom_conversion.h

include/curve/cubic_spline.h

include/curve/curve_abc.h

include/curve/curve_constraint.h

include/curve/exact_cubic.h

include/curve/helpers/CMakeLists.txt

include/curve/helpers/effector_spline.h

include/curve/helpers/effector_spline_rotation.h

include/curve/optimization/OptimizeSpline.h

include/curve/polynom.h

include/curve/quintic_spline.h

include/curve/spline_deriv_constraint.h

python/spline_python.cpp

tests/Main.cpp