MDL-44991 Behat: step to check if attribute does not contain text

The step checks that an attribute exists, but doesn't contain the
specified text.

Example:
Then the "class" attribute of "#mydiv" "css_element" should
not contain "accesshide"
MDL-43673 wiki: verify page tags work as expected

This covers MDL-43109, verifying that saved tags
are available on re-edition of a page, without any warning/error.

Also official tags are verified to be working ok. With support
for multiple options added by MDL-43713 and MDL-43738.
MDL-45148 unit testing: pass role id instead of user id
MDL-45109 - theme/bootstrapbase - Fix Unordered and Ordered lists in RTL mode
MDL-41185 events: Added events for different course view pages
MDL-41185 cleanup course viewed events

Thanks Marina for spotting some of the issues.
MDL-45154 user profiles: category name duplication error
MDL-44950 logstore_database: Make all settings positive for usability
MDL-45075 mod_forum: Move user subscription to an observer

The forum subscription function is called in some cases on forum creation
(specifically the case of an automatically subscribed forum).

Since the forum subscription requires both the course_module instance, and
the context these must both be present when subscribing users to the forum,
however these are not fully set up until after the forum has been created.

By moving the subscription to a subscriber, we are able to hook into the
module creation event after the course_module and context have been linked
to the forum instance.
MDL-41185 fix url in course_viewed event after course deleted

Includes a minor fix for course invalidation after deleting of course,
this improvement should not affect normal execution, that is why
it was not backported.
Merge branch 'w17_MDL-41185_m27_courselog' of git://github.com/skodak/moodle
Merge branch 'MDL-43673' of git://github.com/stronk7/moodle
MDL-45186 mod_quiz: Some RTL improvements on quiz edit page
Merge branch 'wip-MDL-45154-master' of git://github.com/marinaglancy/moodle
MDL-45008 atto_link: Standardise unlinking for non-selections

When placing the cursor within a link, but not making a selection, we
should unlink the whole link.
MDL-40716 report_completion: Set RTL
bump version for new events
Merge branch 'MDL-40716-master' of https://github.com/andrewnicols/moodle
MDL-45194 assign_feedback: Cache was never set and used in is_enabled
MDL-45124 dndupload: Lowercase types when comparing

IE helpfull uses a mixed-case version of 'Text' which fails the string
comparison. All other browsers use lowercase for their mime-types.