New version. 

Change log:

+ New commands (`rules add` and `job-logs`)
+ Finaly remove all GNS mentions
+ Logging refactoring
+ Show traceback if `--debug` option passed

Closed yandex-sysmon/powny-cli#28
Closed yandex-sysmon/powny-cli#18
Closed yandex-sysmon/powny-cli#15

А не `POWNY_API_URL`?