compute_derivate return raw pointer instead of shared_ptr (to use covariant return type, required for python API)

JasonChmn authored Aug 09, 2019 and Pierre Fernbach committed Sep 03, 2019

[Serialization] Add template on save and load function for serialization => Now able to load in abstract pointer

change namespace spline to curve in include folder, rename folder spline to curve, change in the CmakeList.txt