costs → core Relation

File in include/aligator/modelling/costs	Includes file in include/aligator/core
composite-costs.hpp	cost-abstract.hpp
composite-costs.hpp	function-abstract.hpp
constant-cost.hpp	cost-abstract.hpp
cost-direct-sum.hpp	cost-abstract.hpp
quad-costs.hpp	cost-abstract.hpp
quad-costs.hpp	manifold-base.hpp
quad-costs.hpp	vector-space.hpp
sum-of-costs.hpp	cost-abstract.hpp