* New encoding format:
  * Msgpack reports between probe<->app (smaller representation, faster to
    encode/decode).
  * Still use JSON between app<->UI (try to avoid making javascript deal with
    mspack).

  The app still suports publishing reports in both gob and JSON, not braking
  backwards compatibility.

* Use compile-time generated marshallers/unmarshallers for higher performance. In
  order to be able to skip code-generation for certain types, I included
  https://github.com/2opremio/go-1/tree/master/codec/codecgen instead of
  upstream until https://github.com/ugorji/go/pull/139 is merged.

* Encode/decode intermediate types using github.com/ugorji/go/codec.Selfer
  for higher performance and reducing garbage collection (no temporary buffers).