MDL-45239 editor_atto: The editor cannot be active if it is not the active element

FireFox thinks that you can have an active selection on an element which
currently does not have focus. How this can be the case is a mystery.
MDL-45257 mod_assign: Removing wonky feedback_updated event
MDL-45315 block_news_items: Add missing depedency
MDL-27459 Completion: When ratings off, disallow grade completion

For activities that use ratings, there is no grade unless ratings
are enabled. The completion system still lets you select 'complete
when user gets a grade', which leads to later errors.

This change simply disables the 'completion on grade' field if
ratings are enabled for the activity, but not turned on in the form.
MDL-44780 filter_mathjaxloader: switched mathjax filter on by default
MDL-44780 filter_mathjaxloader: mathjax is now at the top of the filter list
MDL-42635 lesson: Fixed error message
Merge branch 'MDL-45315-master' of git://github.com/danpoltawski/moodle
Merge branch 'MDL-27459-master' of git://github.com/sammarshallou/moodle
Merge branch 'MDL-45257-master-2nd' of git://github.com/FMCorz/moodle
Merge branch 'MDL-44780_mathjax_default' of https://github.com/andyjdavis/moodle
Merge branch 'MDL-45239-master' of git://github.com/andrewnicols/moodle