Getting rid of shapeless_contrib and shapeless.Lens

We stick with scalaz Lenses, but in order to reduce the boilerplate,
I implemented function >> of shapeless.Lens for scalaz.Lenses
(more or less copy/pasting from shapeless). Works fine so far.
Also, at the time being, automatic typeclass derivation in
shapeless_contrib seems to not work with custom typeclass
instances. Therefore added some helper in efa.core.typeclass. This
still requires some boilerplate (one line per typeclass instance).
So what?