Add Totals to apache-graphite plugin

This PR adds two extra metrics to plugin/apache-graphite to ensure that we collect Total Accesses and Total kBytes. In order to support a closer view of requests / second. 

Currently mod_status requests Requests Per Sec at Total Accesses / Uptime which isn't terribly useful. 
With this change, you can graphite Requests Per Sec as a derivative on the running total.