* Add status output for sidekiqctl
* A little cleanup
* Refactor to Sidekiqctl::Status
* Error handling for section argument
* Rename workers to processes
* Clean up how the queue table is printed
* Refactoring, added tests
* Improve error handling
* Comma-separate values in overview
* Add changelog entry
On OpenBSD, you can only use getpgid(pid) if the calling process
belongs to the same session as the the process with the PID `pid'.
Otherwise getpgid() returns EPERM.
Using kill(0, pid) is a more portable way to check whether a process
exists.