Deltas from different subtrees should be differentiated

[rtyler]

If you're unfortunate enough to have a consumer named the same thing under the "standard" tree (e.g. /consumes) and the KafkaSpout tree (e.g. /kafka_spout) then invalid deltas will be reported.

Depending on where the data comes from, it should be differentiated in the metrics format IMO

[rtyler]

I think the appropriate way to differentiate these, at least with the metrics-datadog reporter is via tags. For other potential reporters they will need to differentiate up front in the name of the metric instead (e.g. a statsd namespace)