Statsd module



This PR allows us to ingest metrics that come from statsd with simple configurations.  It does not allow us to ingest raw preaggregated metrics.

* DoesStuff - used to push test data into a statsd instance.  Uses a simple statsd client (StatsdClient.java)
* DataTool - used to get serialized data out of cassandra.
* CarbonCompatibleIngest - mimics a carbon ingest instance (replaces graphite).
* Parses statsd lines.  Since timers arrive on multiple lines, we have to treat each chunk of data from statsd as a bundle.  In my observation, timers are never split across bundles (abstracted as StatCollection)

How to test (beyond mvn verify)
1. Start cassandra
2. Start statsd. Set it to listen on port 8125 and push to 8126.
3+4. Start BF in ingest+rollup mode. This can be done using `CarbonCompatibleIngest`.  Make sure to set GRAPHITE_INGEST_ADDRESS and GRAPHITE_INGEST_PORT (to 8126).  This can be one or two processes; I tested with two.
5. use `DoesStuff` to push metrics into statsd. It is documented in its comments.
6. use `DataTool` to query the metrics directly from cassandra.  It is documented in its comments.

Caveats:
* You'll need a differently configured CarbonCompatibleIngest for each statsd that you talk to (to account for different prefixes, suffixes, etc.).