#11 Status subcommand for circologctl

Introduced a `status` subcommand for `circologctl`. It offers a `-format` option with possible values: - `plain` (default); Example output: ``` Buffer Length: 1000 Server Status: unpaused ``` - `json`; Example output: ``` {"status":{"size":1000,"running":true}} ``` - `pretty`; Example output: ``` { "status": { "size": 1000, "running": true } } ```