Migrate to CBOR for Message Serialization

[zicklag]

We need a message serialization format that is not version specific so that different versions of Maxim can reliably communicate to each-other or otherwise determine that they are of a different breaking version and gracefully declare that they are not compatible.

The CBOR format ( rfc7049 ) allows for a compact JSON-like representation that I think will be well suited for this use-case.