Changes to functionality
- Removed syncing of user metadata including gender, location etc.
These are no longer available to standard Facebook applications.
- Removed the remote 'revoke' functionality. No other providers have
it, and it does not appear to be standard practice in other apps.
- The 'facebook_no_email' event is no longer logged. The system can
cope fine with a missing email address.
Data is migrated to the new user_associated_accounts table.
facebook_user_infos can be dropped once we are confident the data has
been migrated successfully.
* FEATURE: Update avatars in posts and revisions when user gets renamed
* FIX: Replace username in deleted posts when user gets renamed
* FEATURE: Replace username in notifications when user gets renamed
FEATURE: Update mentions and quotes when user gets merged
