WIP: statsd / graphite integration.

## WIP

I thought about it for a while and decided that the simplest way to get metrics from statsd into Blueflood will be to have statsd treat Blueflood as a graphite ingestion endpoint.  This PR gets us part of the way there (accepts data from statsd).

Still todo:
* Decide how to handle the special metric types
* Figure the best way of deriving a locator