MDL-38315 Completion: Bugs with 'locked' status in activity form
MDL-38361: Fixed typos in mod/assign/locallib.php
MDL-39084 grade: Capability checks are incoherent for the Course grade settings section
MDL-39185 mod_forum: declare new object before creating member variables to prevent Strict Standards warning
MDL-39167 quiz access rules: need to validate their settings.

We were missing the hook in the form validation method. We had them
everywhere else they were needed.
MDL-39172 Import of .dat files is broken in blackboard_six import format
Merge branch 'MDL-39185_m23' of https://github.com/markn86/moodle into MOODLE_23_STABLE
MDL-30940 form: Mutiple select work correctly without any selection
Merge branch 'MDL-39167_23' of git://github.com/timhunt/moodle into MOODLE_23_STABLE
Merge branch 'MDL-39084-moodle23' of github.com:StudiUM/moodle into MOODLE_23_STABLE
MDL-39050 quiz access rules: settings.php files should work.
Merge branch 'MDL-38361_23' of https://github.com/prateeksachan/moodle into MOODLE_23_STABLE
Merge branch 'MDL-39172_23' of git://github.com/jmvedrine/moodle into MOODLE_23_STABLE
Automatically generated installer lang files
Merge branch 'MDL-39050_23' of git://github.com/timhunt/moodle into MOODLE_23_STABLE
MDL-39050 quiz access rules: $module->is_enabled() not available for 23
MDL-37942 Images with non-alphanumeric chars in file name won't export
MDL-34933 core_message: Adding index to improve database access on message_working table.
MDL-37514 module.js: fix .js for auto quiz submission in preview mode

The issue: when we attempt the quiz as teacher/admin and timer is up,
quiz is not submitted, even though "Open attempts are submitted
automatically" is set. I've changed the javascript for a timer,
responsible for submission, removing the special behaviour in case of
preview mode. Note, that when the admin/teacher is taking a quiz, the
"preview" mode is automatically switched on.

It is a bit strange, since in the javascript there was clearly no
expressed intention to really submit quiz in preview, even when timer
hits. It does not really seem like a accidental bug, rather it looks
like some misunderstanding. Worse still, it may happen that I did not
understand the intentions of previous editor and ruined some
functionality. Because of this, and the fact that this is my first bug,
I would like to ask about the peer review! Please, see my comments in
bug discussion for the testing steps.
MDL-35364 shorten text: don't return invalid HTML.

I also broke the unit tests into more, smaller, named tests, so that
when things start failing, more tests are run, and it is clearer what
the problem is.

In a couple of cases, I adjusted the $ideal lenght in the test. A
careful counting of the characters in the test input (added as comments)
suggests that the new values make for better tests.