MDL-43874 quiz, teacher comments should respect display options.

Whether the comments on manually graded questions were visible to
students should have been controlled by the 'Specific feedback' Review
option in the quiz settings. However, the quiz was not setting
$displayoptions->manualcomment, so it did not work.
Merge branch 'MDL-43581' of git://github.com/timhunt/moodle
Merge branch 'MDL-43773-master' of https://github.com/lucisgit/moodle
Merge branch 'wip-mdl-43766' of https://github.com/rajeshtaneja/moodle
Merge branch 'wip-mdl-43765' of https://github.com/rajeshtaneja/moodle
Merge branch 'wip-MDL-43643-master' of git://github.com/marinaglancy/moodle
Merge branch 'MDL-43757_master' of git://github.com/dmonllao/moodle
MDL-43797 lib/moodlelib.php: Remove custom homepages on user deletion

Change-Id: Ibaf6f0a9dc29d00b97a32111d1cf5063ebed1888
Merge branch 'MDL-43874' of git://github.com/timhunt/moodle
MDL-43797 lib/db/upgrade.php: Remove custom pages for deleted users

Change-Id: Ifef563431682a2a5524927f85ca9eba9cbe520ff
Merge branch '43688-27' of git://github.com/samhemelryk/moodle

Conflicts:
	theme/bootstrapbase/style/moodle.css
Merge branch 'MDL-43450_master' of git://github.com/dmonllao/moodle
Merge branch 'MDL-43246' of git://github.com/timhunt/moodle
MDL-43797 lib/db/upgrade.php: Optimise sql for my_pages deletion

Change-Id: Idf300ab07afda3bcefea80e617549f40c710e529
Merge branch 'master_MDL-43797' of https://github.com/totara/moodle
MDL-42928 JavaScript: Create a module to handle page scroll locking
MDL-42928 JavaScript: Add LockScroll to all modal dialogues
MDL-42928 JavaScript: Disable lockScroll for small chooserdialogues
MDL-34055 add bulk DB->insert_records() method

This patch was inspired by patch by Simon Coggins from Totara.
MDL-40909 mod_forum: removed duplicated test (duplicated in enrol/meta/tests/plugin_test.php)