title: Authenticated Referrals - how to tell if a user just authenticated
body: <p>I have a game where I want to track user logins/installs. I need to be able to detect when a user was just redirected to my app from the authenticated referral dialog. Since we cannot specify our own redirect_uri after the user authenticates, nor does Facebook append any sort of flag for canvas apps - is there any way to achieve this?</p>