MDL-41767 themes: Support for parent-specific sheets in plugins
MDL-41644 Backup: Update CSS class .notifywarning with .notifyproblem
MDL-41646 Wiki: Removed unnecessary wiki_info class
MDL-43838 behat: Clean theme compatibility with small and medium screen sizes
MDL-42882 upgrade: unit tests for root folders upgrade

Just verifying the original behaviour
MDL-42882 upgrade: improved SQL query

Kudos to Tim Hunt who came up with this, on mysql with 4 milion
records (and a fast SSD) the performance difference is:

Original: 36.83 sec
New query: 8.63 sec
MDL-43941 Course: Allow AJAX show/hide of activities in hidden and orphaned sections
MDL-43641 Javascript: Correct default dialogue centering
MDL-32724: LDAP Auth function user_update() returns true even if update has failed
MDL-43978 badges: Display error message to guest users viewing "My Badges" page
MDL-43774 badges: Stop overriding default course navigation
MDL-42882 upgrade: Improvements to upgrade code

Suggested by Petr:
* Don't rely on single user for upgrade
* Make the pathnamehash generation a bit clearer (and add
  a test to verify its correctly formed).
MDL-43946 gradebook upgrade Improve SQL to find duplicate sortorders.
MDL-43200 WebServices: Reset Instance variable
MDL-44029 mod_quiz: Fixing group deleted handler so it does not remove user overrides.
MDL-43978 badges: Fix lang string
MDL-43344 upgrade to latest Flowplayer
MDL-43267 Javascript: Improve accessibility of keyboard move

Change the keyboard move descriptions to allow for more detailed
descriptions such as:
* "After 'X'"; or
* "To top of section 'Y'"
MDL-43267 Javascript: Remove aria drag/drop related attributes for drag/drop

Since we provide an alternative interface rather than describing the
locations for each drop, we should not add aria-grabbed, or
aria-dropeffect.
MDL-43267 Javascript: Improve focus before and after drag/drop