`gaffer.cli` -> `gaffer.gaffer_cli`
bump tornado version in setup.py

while i'm thinking about it ...
simplify the HTTP handling.

There is no real need to listen on multiple endpoints here. It can easily be
done either by using masquerading rules or a prox. This change make the code
more simple and prepare the arrivale of the lookupd server.

While I'm here make sure an unix adress can't be used by a gaffer node since
we won't be abble to register it in a lookupd server anyway.