Remove the ability to call recog methods via m(args)

[ssiccha]

This is something @fingolfin proposed in #263. Currently we can't do this, since for example the method FewGensAbelian explicitly calls KnownNilpotent. If we had something like suggested in #271 then we could tell recog to call KnownNilpotent next and then return. That should resolve most of the situations where currently we call a method directly from inside another method. What do you think @fingolfin?

Of course we could also simply convert all calls of the form m(args) into calls which use CallRecogMethod.

[fingolfin]

I think my proposal was to convert m(args) to CallRecogMethod(m, args) (or whatever the right syntax is).

As such, I am not sure what the problem is in FewGensAbelian, nor do I understand how this relates to #271. It feels as if you had something more in mind than what you actually wrote down above?