Facebook email verification

This PR gets the client ready for our facebook email verification system that augments the giveaway.  It adds an action-link that will be used in the verification email that we send to users, and it introduces the 'invalid_fb_email_token' and 'fb_email_unverified' reward states.
This is causing the error to be reset to null. We want to open the facebook reward pane without clearing the error.