Add a Stats object that can be used to increment and access counters.
Remove parens.
Changed logic to only take counter name but assume a fixed group.
Also print custom counters after job completes, based on a command line arg.
Rename custom counter group.
Dump custom counters by default.
Allow counters to use groups.
Merge pull request #733 from azymnis/feature/stats_counter

Add a Stats object that can be used to increment and access counters.