benchmarks added.
statistics: rate added.
config: "statistics"->"rate-unit" option added (rate is computed per that time unit).
message_queue: use 'values'->'rate' statistic for pop_count stats instead of 'incr_deltas'->'moving-sum'.
benchmarks/load: step option supports 0 as rate (sleep for time_limit) and 0 as time_limit (skip this step).
metrics: counter's incr_deltas, decr_deltas, deltas statistics removed.
benchmarks/load: "incr-deltas", "decr-deltas", "deltas" config sections of "metrics"->"counter" removed.
config: redundant json node "values" in "metrics"->"gauge", "metrics"->"counter", "metrics"->"timer" removed.
json: redundant json node "values" in metrics json dump removed.
benchmarks/load: redundant "values" json node removed from config.
statistics: entropy added.
statistics: moving interval statistics accuracy fixup/improvement.
benchmarks/load: compile warnings fixup (unused variable).