Erlang based metrics system inspired by Coda Hale's metrics

 Folsom is an Erlang based metrics system inspired by Coda Hale's metrics
 (https://github.com/codahale/metrics/). The metrics API's purpose is to collect
 realtime metrics from your Erlang applications and publish them via Erlang APIs
 and output plugins. folsom is *not* a persistent store. There are 6 types of
 metrics: counters, gauges, histograms (and timers), histories, meter_readers
 and meters. Metrics can be created, read and updated via the `folsom_metrics`
 module.