[Openid-specs-ab] Username

[Justin Richer]

I might be missing it, but it seems that there's a gap for specifying a 
user's preferred local username in the User Info schema. This is 
distinct from "user_id" which is a guaranteed unique identifier, "name" 
which is the actual name of the person, "nickname" which is a shortened 
first name, or anything else that I can see.

Is there a specific reason for this omission? If not, I'd like us to add 
in a standard claim for this information.

  -- Justin