add new function "calculate latency average"
Use Async process and enable to watch status on stats
Add new async process for calculate latency average & add some commands for change setting.
Kick calculate latency average by time (not count)
Add method of calculate qps.
Unify chk_cnt to latency_sum by using multi layer hash
calculate latency average by use update latency data not all sum
modify ongoing setting changing cmd.
change qps logic
fairing code
delete debug comment
Merge branch 'time' into release_v0.8.13

Conflicts:
	ruby/server/lib/roma/command/sys_command_receiver.rb