MessagePack parser

This adds a generic MessagePack parser with date partitioning, much like the JSON parser. Includes unit tests.

If there is interest in merging this I can definitely poke around the integration test to make sure this is fully tested end to end (I did test it manually), or if someone has any quick pointers it would be appreciated.

I haven't written Java in quite some time so I'm sure it'll need some fixing up.