MDL-44573: Remove HTML tags in outputs column in offline grading worksheet
MDL-41284 stop using log table for login weekly and monthly stats

We already have stats for each day, the SUM is what we want there...
MDL-41284 hack stats to use new log readers if available
MDL-44106 add WS_SERVER constant to all web service calls

This will help us hack around some nasty webservice problems,
such as require_login() and it will be used to set proper 'ws' origin
in logged events.
MDL-44106 add origin info to $PAGE object and use it in logs
MDL-44107 deprecated event_base::can_view()

The problem is that it would be too expensive and difficult
to implement reliable access control in each event.
MDL-44107 deprecate can_view() in feedback events, to be replaced by is_anonymous()

See MDL-44661 for more info.
MDL-44510 support PHPUnit 4.x

The old style PEAR installation is incompatible with PHPUnit 4,
nobody was supposed to use PEAR any more - composer
is the only supported library installation method now.
MDL-37148 pix: make default user images smaller
MDL-44682 fix bug in decompose_update_into_safe_changes
MDL-44704 core_message: always use system context when triggering a message_sent event
MDL-43784 theme: Removing all the old themes
MDL-44690 core_questions : download of question steps data as csv file
MDL-42575 mod_page: revert heading option display

Reverted heading option display for page resource; made sure to not re-introduce class issues.
MDL-41285 block_recent_activity: behat test for structural changes
MDL-41285 blocks: recent activity does not use log table

instead it defines it's own table and stores the necessary events
MDL-41285 blocks: capabilities to view structural changes in recent activities
MDL-44686 behat: limit failure filename length to 255 chars
MDL-40915 events: Add events for calendar actions

 Added a calendar_event_created
 Added a calendar_event_updated
 Added a calendar_event_deleted
MDL-40915 events: Replace add_to_log with events in calendar