Merge branch 'MDL-31122-m21' of git://github.com/sammarshallou/moodle into MOODLE_21_STABLE
MDL-31224 navigation: Added JSON handling on action_link objects to the navigation
MDL-30509 backport perf improvement in role cleanup in cohort sync

This patch simplifies the role cleanup sql, it is not necessary to look for roles without enrolment instance because all roles are automatically unassigned when deleting enrol instances.
MDL-31385 quiz: does not resume previews.
Automatically generated installer lang files
Merge branch 'install_21_STABLE' of git://github.com/amosbot/moodle into MOODLE_21_STABLE
weekly release 2.1.4+
Updated bugfix according to Jerome suggestions

password check is done at lib.php instead of externallib.php

Conflicts:

	user/lib.php
MDL-30878 core_user_update_users user password is reset if not specified
MDL-31317 original_site_identifier_hash falls back to null during the backup conversion

Even if the site identifier is not defined in the source 1.9 backup then the
converted 2.0 version should still contain the element to prevent PHP
notices on direct assignment.
MDL-29471 php warning when adding function to a new web service
MDL-31015 File/URL resource 'Open' and 'Force download' options should work consistently

Conflicts:

	mod/resource/lib.php
	mod/url/lib.php
Merge branch 'MDL-31385_21' of git://github.com/timhunt/moodle into MOODLE_21_STABLE
Merge branch 'MDL-26260_21' of git://github.com/timhunt/moodle into MOODLE_21_STABLE
MDL-30854 quiz/question editing: fix create calc question & add on page.

This was one of those innocent seeming issues where, once you start
digging, you find a mess. In this case, the code that is now in
question_wizard_form::add_hidden_fields used to exist in four different
places, in four inconsistent versions. This is now all nicely
re-factored, and that solves the problem.

Along the way, I found and fixed some wrong string references in
qtype_random, and stripped out some unnecessary &s in function
declarations.

Conflicts:

	question/type/calculatedsimple/edit_calculatedsimple_form.php
MDL-31314 gradebook restore: fix category.depth on restore.

Without this, restoring backups made with the OU's custom 'restore from
1.9' feature, and possibly other people's custom converstion code, does
not work properly.

Also, fix poor recordset code.
MDL-30484 question engine: don't lose response files when regrading.

The problem was mostly that, in the past, we did not worry if
question_attempt_step.id changed during regrade (because we deleted the
old step row and inserted a new one). However, now that steps can have
associated files, we can't be that slack, becuase the step id is used as
the file itemid.

So, now, we have to update the existing rows during a regrade. We do
this by having the question engine tell the question_engine_unit_of_work
that the step has first been deleted, and then added back. Then we make
the unit-of-work spot that delete + add = update.

This also means that during regrading, we have to pass around some extra
ids so that new steps know the id of the step they are replacing.

Naturally, this requires some quite trickly logic, so I finally got
around to writing unit tests for question_engine_unit_of_work, which is
a good thing.

Along the way I also got around to renaming
question_attempt->set_number_in_usage, which got missed out when
everthing else was renamed to slot ages ago.

Finally, while working on this code, I noticed and fixed some PHPdoc
comments.
MDL-31426 forum: don't show/allow any subscription to not enrolled users
MDL-31428 forum: prevent some warnings with debug enabled
Merge branch 'MDL-31428_21' of git://github.com/stronk7/moodle into MOODLE_21_STABLE