Make connected users' ip addresses available from hookbox admin page (and possibly web apps via hookbox)

[codeorca]

Sometimes it can be useful to know who is interacting with the web app and whether connected users are unique persons/machines or one with multiple browsers or browser tabs connected to the page. Allowing admins to see the ip addresses of connected users via the admin page would help to this end. Allowing the web app itself access to connected users' originating ip addresses would help in cases where you wanted to restrict access to the web app to certain ips, etc.