CSVSummaryReporter

Initial version of the CSVSummaryReporter. Should and will have a lot more output options, but the total time is what I want most at the moment.

Reviewer: @daithiocrualaoich 
Depending on whether we want to output the total all the time, it might actually not be necessary. I initially thought that this could just scan reversely within an interval of the current day or something. Maybe this is a bit of premature optimization. I think we can wait and see how long (and how much memory) it's going to take once you accumulated a couple of months worth of data.