MDL-41071 core: plugininfo_mod caches in plugininfo_mod definition
MDL-40952 skip only the opcache requirement in environment test

Please note we need other optional extensions and settings because otherwise some tests fail without explanation.
MDL-41094 purge caches only before and after upgrade of plugins

It should not be necessary to purge before/after individual plugins
because caches are disabled during install and upgrade.
MDL-41112 fix theme and js caching info in config-dist.php
MDL-41125 course: Only require dndupload library when necessary
MDL-41122: Trim on RSS body to prevent Remote RSS block from failing on valid feeds
MDL-41136 badges: Prevent extra loading due to unnecessary includes
MDL-39474 introduce $CFG->debugdeveloper and cleanup $CFG init
MDL-41159 theme: Remove z-index from file manager context menu icon
MDL-39956 cohort: Convert to new events

* \core\event\cohort_created
* \core\event\cohort_updated
* \core\event\cohort_deleted
* \core\event\cohort_member_added
* \core\event\cohort_member_removed
MDL-39956 cohort: Add tests for new events
MDL-39956 cohort: Event clean up and made ready for integration

* Added more PHP Documentation
* Localised strings for get_name()
* get_legacy_eventname() is now static
* get_legacy_eventdata() is now protected
* Testing legacy event data
* Added missing defined('MOODLE_INTERNAL') checks
* Added missing call to add_record_snapshot()
MDL-41157 calendar: add unit tests for calendar_get_course_cached
MDL-41157 calendar: improve calendar_get_course_cached

The function get_course() introduced in 2.5.1 will use $COURSE and
$SITE to avoid an uncessary DB query, simplifying the logic of this
function and improving perf.
MDL-39851 javascript: Add behat fix for filepicker

The filepicker was changed to use M.core.dialogue - this
patch updates the behat suite to search the changed dom for
the file picker windows closed event.
MDL-41019 bump redirect_if_major_upgrade_required()
Merge branch 'MDL-36002-master-fix1' of git://github.com/damyon/moodle
MDL-39954 event: Fixed namespace issue with \coding_exception
MDL-39954 event: Fixed errors raised while triggering event
Merge branch 'MDL-39954-master' of git://github.com/FMCorz/moodle