pass termCh to mainloop for loop controll
wait up to 30 seconds for terminating until `postQueue` is empty
add test for terminating
remove unnecessary loop
change broadcast terminating timing
output error message when the post values are abandoned
add comments
add comment
Darwin filesystem support for spec and for metrics.
Merge pull request #43 from hiroaki0404/spike-darwin-filesystem

Darwin filesystem support for spec and for metrics.
remove `exitCh <-` in main loop, use direct return
s/loopStateTerminated/loopStateTerminating/
define NewPostValue for struct initializer
use defer Luke
fix nit changes
Merge pull request #42 from mackerelio/feature/graceful-quit

Feature/graceful quit