Bugfix

1. Fixed #1 , workers were not stopped correctly.
2. wake up stats thread to clear stats.

Changelog

1. change the format of keys in errors map, use md5 hash as locust does.
2. add more docs.

Features

1. Run as a locust slave, only support zeromq protocol.
2. Support max RPS limitation.
3. Support dry-run for debug purpose.