First version of dragdrop matching question created by Adriane Boyd upgraded to Moodle 2.3
Similar fix to MDL-36683 / MDL-30018 for match
Update to use YUI3 and simplified HTML structure
Correct display for non-javascript version.

I'd forgotten to check the display when js is disabled after making some
other changes to the renderer previously.

Since we no longer pass the HTML in as a JS param, we no longer need the
non-raw option. Removing it to reduce complexity and unnecessary code.
Remove inadvertant comment from YUI3 commit
Remove use of browser checks for AJAX drag/drop.

YUI should handle this fairly gracefully already. It's safest not to do
this in php because User Agents change, and new browsers emerge.
Tidy up some of the unused styles and add examples of their replacements
Cast type of selected to int
Merging Andrew changes
Fix some styling issues
Lots of Codechecker errors fixed
Remove obsolete help file
Merge branch 'ddmatch-yui3' of https://github.com/andrewnicols/moodle-qtype_ddmatch
CONTRIB-4015 images in distractors no shown
Update xml export to current standard
fix bug in xml import and in notice
Increment version for submission
small change to README
Improve restoration of 1.9 backups
CONTRIB-4437 course restore fails - table question_match doesn't exist