MDL-39667 repository: Correct check for uniqueness of the name
MDL-39412 question behaviours: hide manual graded option

The ability to set all your quiz questions to require manual grading is
an interesting possibility, but practically almost useless.

If you set that accidentally, then you are badly stuck. There is no way
to fix it after the students have answered the quiz.

Therefore, we should set the config option to hide that option from the
UI. We do this for all Moodle sites as part of the upgrade, not just for
new installs.

If any admin wants to re-enable this, they can later.
MDL-39412 disabling manual graded behaviour refinements

1. Change behaviour admin settings so you can only select enabled
behaviours.
2. During the upgrade, change admin settings that might be currently set
to manual graded, so that instead they are set to deferredfeedback (if
that is available. If not, we just take the first alphabetically.)
MDL-39412 Prevent developer warnings on upgrade from 24 to master
MDL-39761: mod_assign: Always check submission plugin status and visibility.
MDL-39947 mod_forum: Add safety check to variable assignment when counting unread posts
MDL-33562 lib: remove private keys when user deleted
MDL-33562 lib: remove deleted user tokens
MDL-39650 form: Type can be set on repeated elements in a group
MDL-39971 each attempt builds on last broken for previews.
MDL-40009 notes: corrected the form element names passed to setType
MDL-40018 theme_sky_high: Fixed footer in admin pages.
MDL-36090 core_grade: added logging of overriding of student grades
MDL-25901 rss: do not copyright html tag

They copyright field does not permit html, it should be plain text
MDL-26925 User selector: Set label when no results

Thanks to Jonathon Fowler for the fix!
MDL-39832 Files: Revert MDL-39688 commit, 6ce0c9ce42fa7849e67d7611a628ece51c336c5f

MDL-39688 has been successful in providing a solution for the issue but further
investigations done in MDL-39832 have got the evidence that the given solution
is more likely a workaround.
MDL-39832 Files: Fixed ETag format according with RFC2616.

ETag must be double quoted,
http://tools.ietf.org/html/rfc2616#section-3.11:

      entity-tag = [ weak ] opaque-tag
      weak       = "W/"
      opaque-tag = quoted-string
MDL-32480 fix display of IMS content packages with external links
MDL-32480 allow external https links in IMSCP too
MDL-37780 fix 1.9 restore on windows