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.
v2 also has a "conversions" package containing extension methods that can turn a v1 `Managed` into a v2, and vice-versa.  Just import com.rojoma.simplearm.v2.conversions._ and use ".toV2" and/or ".toV1" as appropriate.