Removing some legacy code/comments, an update hook from multihoice -> 6.4 which we will never be running in 7.
Issue #2378669 by djdevin, carlospdl: fixed and added tests for critical issue with categorized random questions not building question layouts properly
Issue #2387085: fixed multichoice row highlighting, and fixed across multiple mcqs on a page.
Issue #2387045: fixed label appearing when setting auto quiz title
Issue #2374407: improved revisions actions page, and made it work