Added OIDC Conformant UserInfo class and API Method

[cocojoe]

Public API Added (Open to name changes)

• func userClaimInfo(token: String) -> Request<UserInfo, AuthenticationError>
• public class UserInfo: NSObject, JSONObjectPayload

This adheres to the standard claims specification, although we may not support all claims. I feel we should support all properties for developer convenience. For example Facebook openid profile will return.

{"sub":"facebook|1010000000000","name":"Martin Walsh","given_name":"Martin","family_name":"Walsh"
,"nickname":"martin.walsh"
,"picture":"https://scontent.xx.fbcdn.net/v/t1.0-1/p50x50/myawesomeprofile.jpg"
,"gender":"male","locale":"en-US","updated_at":"2017-06-09T14:49:21.310Z"}

[cocojoe]

I need to add tests, just wanted to open up any further discussion.
Could possibly deprecate the old userInfo.

[hzalaz]

And if we do

let publicClaims = ["sub", "name", "given_name", "family_name", "middle_name", "nickname", "preferred_username", "profile", "picture", "website", "email", "email_verified", "gender", "birthdate", "zoneinfo", "locale","phone_number", "phone_number_verified", "address", "updated_at"] // This can even be a static thing outside of the class since it won't change
let customClaims = json.filter { !publicClaims.contains($0.0) }

?

[cocojoe]

I agree publicClaims should be static.
The issue with filter here is it will return an array of tuples, so it's not quite as elegant as this one liner suggests.
In Swift 4 this works as a filtered dictionary will now return a dictionary. (As it should really)

[hzalaz]

Let's try to keep the userInfo name

[hzalaz]

Try moving this to other file since its shared