Merge branch 'install_28_STABLE' of https://git.in.moodle.com/amosbot/moodle-install into MOODLE_28_STABLE

Event generation and completion should be generated only once.

Note: Added small fix to unit test.

The fields are:
- username
- idnumber
- institution
- department

This patch fixes the updating of calendar events when the course
is reset and its start date is changed.

The YUI notification dialogues will now set the appropriate
aria attributes when they are shown/hidden to allow screen
readers to navigate them correctly.

When the dialogue is shown all background elements will be marked
as hidden while the dialogue is marked as visible to a screen reader.

When the dialogue is closed the modified elements will be reverted
to their previous state and the dialogue will be marked as hidden to
a screen reader.

Merge branch 'MDL-51305_28_too_many_gradeitem_fetches' of https://github.com/colin-umn/moodle into MOODLE_28_STABLE

Mark Nielsen authored Sep 22, 2015 and Dan Poltawski committed Sep 28, 2015

All of these changes make use of already
fetched grade data.  Without these changes,
the gradebook regrade process does not scale
well with very large courses because it fetches
many grade records, one at a time.

Signed-off-by: Yuliya Bozhko <yuliya.bozhko@totaralms.com>

Conflicts:
	lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor-min.js

Conflicts:
	lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor-min.js

The change in MDL-51090 broke manually commenting on questions for which
no mark is given (max mark == 0). This fixes it, with unit tests.

Thanks to Nick Phillips for the original suggestion of the fix.

Credit to Andrew Nicols.

This improves the speed of returning a list of
cohorts. Thanks to François Gannaz for providing
this patch.