Merge pull request
#1471 from minrk/connection
simplify IPython.parallel connections and enable Controller Resume
Rolls back two-stage connection info, putting more information into the connection files. This makes it easier to use hand-crafted ssh tunnels, as all ports are read from the file, rather than from the reply to registration/connection requests.
It is no longer possible to connect to the Controller without a connection file.
Adding the serialization method to the connection file also makes it harder for custom serialization to result in a mismatch in configuration between the various objects.
