Login via OpenID

Now this allow user to login via multiple OpenID accounts, I'll implement the web part after this and see if it will confuse the Interface part or I can fix it later if I find using just one account is more suitable. Any idea ? :)
I think the user ID in this case must be the OpenID, i.e. the user's URL.  Otherwise there may be username conflicts/takeover possibilities.

It may be useful to ask for email (not publicly visible) in addition, as that way we have a means of contact.  The logging in user usually has a chance at their OpenID provider to allow/deny requests for additional information.