Added basic printing server.

I'm still getting the hang of communicating over the network in rust. Heck, I'm still getting used to rust. I'm starting off raft with a basic client/server. This implements a server that prints the messages line by line that it receives.

To test it out, you can use telnet. For example, in one shell run:

    $ raft server

and in another shell run:

    $ telnet localhost 9999

then type away.
Both. `raft client` will launch the client and `raft server` will launch the server.