Use std::copy over memcopy

[tscrim]

I've seen some posts saying that the former is faster than the latter. Moreover, there are some places where handling the copying directly could be faster (e.g., List::erase).

[jdemeyer]

I assume that you mean memcpy (instead of memcopy). Really, with modern compilers, there should be no performance reason to prefer std::copy over memcpy. I would still argue that std::copy is better style, but I doubt you will gain performance.