* Move up the UPDATE query on wl_notificationtimestamp up to before scheduling the EnotifyNotifyJob
* Move up the SELECT query fetching the users to be notified to before the UPDATE, and use its result for a more efficient UPDATE
* Pass actuallyNotifyOnPageChange() and the EnotifyNotifyJob an array of user IDs
* Add UserArray::newFromIDs()
* Change PageHistory::fetchRevisions() to return a result object instead of an array of rows.
* Stylistic issues: use foreach( $res as $row ) instead of while( $row = $dbr->fetchObject( $res ) ), change a couple of variable names, use __METHOD__.
There should be no functional changes.
* Defer load of groups data
* Introduce newFromRow()/loadFromRow() to allow bulk loading of user objects from a result set
* Hook email and email authentication save/load to allow CentralAuth to provide a global email address
* Defer save of user data after confirmEmail() and invalidateEmail(). Caller must now also call saveSettings(). This reduces the master query count in some code paths.
Elsewhere:
* Introduce UserArray class, for bulk loading of user objects. Immediately useful in email notification, potentially useful for proposed user alias feature.
* In Special:Confirmemail, remove useless handling for impossible false return from confirmEmail()/invalidateEmail().
