starting one-way trip

Added tests for the current json serialization.
The purpose of the one-way trip is to persist the output into files, so we can verify that we can deserialize them back to protocol case classes as we change the serialization format and/or the case class.

/cc @jsuereth 

Yeah.  Let's paint the bikeshed and use transit.


More specifically, I think we may be able to do something about this when we define a pickler "format" for JSON