Add RequestId, 4x4 logging and metrics

Adds logging of the following headers: `X-Socrata-RequestId` and `X-Socrata-4x4`.
Adds standard codahale metrics logging and graphite reporting for HTTP requests.
It would be nice to actually be able to set loggingRate in the things that use it, I suspect that for some things it will be extremely noise at this rate so we may want to tweak it...