MDL-47183: viewhiddenactivities should use the module context

Thanks to Paulo Matos for the forum part of this change.
MDL-46215 mod_forum: Improve style of subscription state

With the implementation of per-discussion subscription, the current
discussion's subscription state must be shown.

Since this state belongs to the discussion rather than the forum, it
should be shown accordingly.  This change therefore includes the addition
of the discussion name as a heading on the page.
MDL-47559 user_menu: customusermenu setting
Merge branch 'MDL-46215-master' of git://github.com/andrewnicols/moodle
MDL-814 forum: provide cancel button when posting

This is the way to clear atto drafts
MDL-47585 stats: fixed incorrect user dropdown
MDL-47914 report_stats: better handling of user and mode
Merge branch 'MDL-47183-master' of git://github.com/andrewnicols/moodle
Merge branch 'MDL-47559-master' of git://github.com/jethac/moodle
MDL-47183 post-integration fixes

* Fixed typo with context_module::instance
* Fixed use of $mod->get_context()
MDL-47559 User menu: version bump for new settings
MDL-47870 tool_monitor: Fix event select dropdown
Merge branch 'MDL-814-master' of git://github.com/danpoltawski/moodle
Merge branch '47914-28' of git://github.com/samhemelryk/moodle
Merge branch 'MDL-47870-master2' of git://github.com/ankitagarwal/moodle
MDL-47562 gradebook: Select view labels fixed and headers updated.
MDL-47562  gradebook: User and Item search on each screen.

Added header for Select screen.
CSS fixes for alignment too.
MDL-47562 gradebook: CSS Styling update.

   AMOS BEGIN
      CPY [selectuser,mod_assign],[selectuser,gradereport_singleview]
   AMOS END
MDL-47562 gradebook: Fixes for exclude and override all in Singleview.
MDL-47562 Grades: Style for the Single view