Refactoring open channels

I want a little more flexibility when opening channels. The main
motivation is to create automatic "Splitters" and "Joiners". The ways it
was, that was not possible.
Adding a minor niceties.

A little documentation here and there, plus a sugar method.
Fixing stupid bug
Adding "auto spltter" feature.

New command "spawn_splitter" and "spawn_socket_splitter" make life
easier when splitting data, we don't need to add individual writer names
anymore.