Log Message:
Update to 3.3.3

Upstream changes:
Highlights

    MDL-59798 - Assignment: Show Due Date in calendar for teachers and managers
    MDL-36580 - External Tool: backup/restore consumer key and secret (on the \ 
same site only)
    MDL-57560 - Show file upload progress bar in Boost theme
    MDL-37810 - List custom roles in the filter on Participants page

Security issues

A number of security related issues were resolved. Details of these issues will \ 
be released after a period of approximately one week to allow system \ 
administrators to safely update to the latest version.
Fixes and improvements

    MDL-52131 - Respect comment format in questions manual comments when Plain \ 
text area editor is used
    MDL-55849 - Assignment: Reopening a group assignment should not create \ 
additional attempts for each group member
    MDL-59909 - Fixed error in ad-hoc refresh_mod_calendar_events_task that \ 
caused exceptions and very long cron run time
    MDL-59780 - Restore MathJax filter settings that were lost in previous upgrades
    MDL-54540 - External tool: Allow to switch to full screen mode
    MDL-51892 - Better explaination of the reason for failed logins in the logs \ 
report
    MDL-57055 - Label resource: allow to access "Label administration" \ 
without Administration block on the "Edit label" page
    MDL-53244 - Show error message when incorrect CAPTCHA is entered on sign-up page
    MDL-57477 - Fixed configuration of PHP 7 sessions using memcached (3.x.x)
    MDL-59854 - Forum: Avoid creating duplicate subscriptions due to race conditions
    MDL-60366 - Feedback: fixed upgrade script (introduced in 3.1.6 and 3.2.3) \ 
that deleted valid multiple anonymous attempts. If your site was affected, \ 
please follow MDL-60592 for the script that restores accidentally deleted data.