Almost-working no-paxos getroot() test.
I've implemented almost everything that we need for using puppet to
tell client_driver to send a 'getroot' message to server_driver, which
will respond with '/', including stubs for start-up.
It doesn't quite work yet---there's a bug in the RPC message content
somewhere. Adding logging (w/ __LINE__ and __FILE__) should make it
much, much easier to debug this.
Added docs for Json RPC formats.
Merge branch 'master', remote branch 'origin'