OAuth Support

[michaelrsweet]

OAuth seems to be where cloud-based printing is going and PAPPL will need to support it for Proxies as well as normal print server operations. Tasks:

• Import mOAuth client code and adapt for use with proxy and server (introspection).
• Add support for URL authentication services that force the use of OAuth instead of PAM.

Admin and print groups should map to OAuth scopes.

[westurner]

With large numbers of printers, organizing printers in a tree-based view is nearly essential.