Expose creator of public queries(when available)

Fix #729.

Signed-off-by: Don Naegely <naegelyd@gmail.com>
@bruth I was guarding against the possibility of empty usernames. So, there might be a valid user but maybe the app uses an email address for its users rather than the username so we might get a valid user but the username field might be empty. While we don't have any apps that do this, I was just trying to account for that possibility. I have no problem removing the username check though and just checking for user.