Documentation - Authentication method slightly unclear

[stutwoby]

I was working on a project recently using the CloudPrnt SDK and we attempted to use the username/password combo for authentication. It might be obvious in hindsight but it would be good to include some detail in the documentation relating to how the username and password gets passed up and to include that it will only be passed up if the server provides a WWW-authenticate header.

[CupNoodles]

In case this is helpful to anybody in the future - it appears that the Basic Auth header values are only sent from your printer if the server responds with an HTTP code 401 Access Denied as well as the WWW-Authenticate: Basic header.

Testing on an mc-print3, this is true for all communications initiated by the printer, so POST/GET/DELETE all need to try once without the headers and get the 401, after which it'll retry the same request with username and password in the header.