[WIP] Replace log with logrus

[nlamirault]

See #17

[iwilltry42]

Finally! Thanks a lot for starting work on this :)

I have some suggestions here:

• You could import logrus like this: log "github.com/sirupsen/logrus" and keep on using log.XYZ instead of replacing every instance of log with logrus
• Everywhere, where the logged message starts with a "level" like "ERROR:", "WARN:", "DEBUG:", or something the like, you could replace the log.Println with the appropriate levelled logger of logrus, e.g. log.Debugln or log.Errorf and so on.

Thanks again, I really like to see the logging improving 👍

[iwilltry42]

LGTM! Thank you very much for your contribution :)

[iwilltry42]

Thank you @nlamirault !