Allow Class Resources, call #to_s for defined resource_name

[kevinjalbert]

If using a class as the resource:

resource Order do
end

The resource_name will be a class, which causes issues when sorting for
sections. By calling #to_s on the args.first when first dealing with
the resource we can ensure that we are always working with a string for
the resource_name.

---

Also refactored to use a ternary operator instead of a one-line if else end.

[oestrich]

Thanks!