Configuration using YAML

[denizdogan]

I think it would be nice if we could configure this using YAML instead of JSON. JSON often becomes messy when editing via SSH on a remote server somewhere, whereas YAML is simpler when typing.

[mageddo]

As it would be simple to create YAML configuration extension along JSON which will remain the default for now, I see it as nice feature. I will take a look how hard it's to add YAML support or any other format and give a feedback.

[mageddo]

#594 will make this issue viable, the JSON structure proposed there will be used for the YAML configuration that will be created