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-39971 each attempt builds on last broken for previews.
MDL-39978 Essays with files break each attempt builds on last
MDL-39865 navigation: 'Profile settings for ...' always displayed

Before this patch, 'Profile settings for X' would only be displayed
if X can access the course, which means that if the course is hidden
the node would be hidden as well. We changed this so that the user
needs to be enrolled in the course.
MDL-39865 navigation: Removed unaccessible repositories node

A user is not allowed to edit another user's repositories, in any
circumstances. The repositories node under 'Profile setting for X'
does not make sense under those conditions.
MDL-39820 theme_bootstrapbase: Fix form button alignment for badges.
MDL-40018 theme_sky_high: Fixed footer in admin pages.
MDL-39773 bootstrapbase: add style for .centerpadded.
Relocate .centerpadded styling from standard to base themes
MDL-39964 report_progress: don't browser sniff for SVG support

Use feature detection, its more robust and better practice.
MDL-39940 tags: missing setType call
MDL-25901 rss: do not copyright html tag

They copyright field does not permit html, it should be plain text
MDL-40036 user: Respect capability to ignore user quota
MDL-26925 User selector: Set label when no results

Thanks to Jonathon Fowler for the fix!
MDL-39979 navigation: Remove the use of an undefined variable
MDL-40013 Easier to override saving question hints

This adds 3 new methods, called from question_type::save_hints,
to make it easier for different question types to overload this
functionality without duplicating code.

Question types that will benefit from this change include
oumultiresponse, ddmarker, preg and correctwriting.
MDL-39832 Files: Revert MDL-39688 commit, 161be9206571787557eb5c11ee440c9e6ae93ca8

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