Concept implementation in C++14 constexpr/SFINAE Based on : http://wg21.link/p0800r0 http://wg21.link/n4674 http://wg21.link/p0734r0 https://github.com/ldionne/dyno/ http://en.cppreference.com/w/cpp/concept https://youtu.be/PJwd4JLYJJY
