MDL-46391 messages: Display search button under contact list.

Add search button to only Message navigation -> Contacts section.
MDL-47301 libraries: Update Typo3 to v4.7.19
MDL-47301 libraries: Patch Typo3 for Moodle's use
MDL-47474 Calendar export: Fix user id in authorization check
MDL-47303 libraries: import latest jQuery library and friends
MDL-47477 libraries: use smoothness theme for jquery ui
MDL-47484 atto_indent: Prevent loss of rangy markers in some cases
MDL-47481 Availability: Profile condition error if no users
MDL-47476 qformat_learnwise: rest in peace.

Learnwise was an old LMS that no longer exists. (Last reference found on
Google from 2009.) So we are removing the ability to import questions in
that format.
MDL-46481 backup: implemented quick backup process (one click)
MDL-46481 backup: behat tests for the quick backup button
MDL-28075 question editing: sort out nav bar when editing in a quiz

If you edited a question from the Edit quiz page in a quiz, the navigation
bar was far too long. This was due to some odd code that was trying too
hard to be clever.

Instead, editing a question is now always treated as being logically within
the question bank for the purposes of navigation. That is, even if the
returnurl will end up taking you back to where you where when you have finished.
MDL-28075 question editing: tidy code

Remove an unnecessary else (the if, and else if, always end in a redirect)
and unindent that code.
MDL-47518 report_log: Logfiles of single users no longer accessible

* Removing join on courseid if it is the SITEID.
MDL-47132 quiz: move question bank extensions to classes/question/bank

While doing this code clean-up, I noticed that the question bank pop-up was
only showing the question name, whereas it should have been showing the
question name and the start of the question text, so I fixed that.
MDL-47132 quiz: move the remains of editlib.php to locallib.php
MDL-45893 user_menu: based on action_menu, new responsive approach
MDL-47299 libraries: upgrade PHPMailer to 5.2.8
MDL-46182 Inefficient query during Moodle upgrade on course_section table.

This part of the code is changing an index on the course_sections table to be unique, for this to happen in the upgrade script the index must be deleted and then the new version added.

Before this change the following was being done:

* The index is removed
* A query to delete records that were not unique on this index is performed
* The unique version of the index is added

After this change the following happens:

* A query to delete records that were not unique on this index is performed
* The index is removed
* The unique version of the index is added

When the original index is present the query uses it, which greatly improves the execution plan.

Before the change an upgrade on a site with around 387967 course_section records the upgrade would be stuck on the delete query for many hours, after the change the time can be measured in minutes.
MDL-35618 enrol_manual: Add possibility to manually enrol cohort members