Rewrite the MemoryTransport to be more similar to the TcpConfig

[tomaka]

The problem with the memory transport right now is that it's too limited. We can't test discovery with it, for example.
Instead we should, in my opinion, allow addresses like /memory/<port>, and have some sort of static global hub similar to localhost TCP/IP connections.

Considering the usage of MemoryTransport everywhere, I would suggest creating a different struct and deprecating the old one, instead of simply rewriting the code.