Allow specifying special member functions with DYNO_INTERFACE

[ArekPiekarz]

As in title, is it possible to do it now? Can dyno::CopyConstructible{} be used for that?
So far I wasn't able to write a compilable form of it.

[ldionne]

Good point; the DYNO_INTERFACE macro does not allow specifying special member functions at the moment. I'll need to think of a solution.