#7 make --talk and --listen less confusing

[Emin Martinian]

Christian Stork pointed out that the --talk/--listen
terminology is confusing and poorly documented:

> It wasn't immediatly clear to me how I have to set
the --talk/listen
> options to add_peer. I think it might be a good idea
to simply say that
> --listen is essentially always the same, ie the
communication mode
> (active/passive/mail) of my local box, whereas --talk
always refers to the
> mode of my peer. (Maybe, the option could even be
renamed to
> --local/remote-mode or something.)