Third party client permissions

[mitchelljkotler]

Third party sites which use squarelet to login can be given permission to read user profile data, so they can stay up to date with things like which orgs a user is in. Right now we can only give full read access - it would probably be good to only give access to users who have explicitly logged in to that site before. Can we hold off on this until we are ready to add more logging and tracking of which sites users are logging in to?