MDL-25901 rss: do not copyright html tag

They copyright field does not permit html, it should be plain text
MDL-31680 Correcting the format of calculated types correct response
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-40080 Remove unused strings from the core_hub subsystem
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, f111746140fe80a821ae69e3bf518d950bf188a1

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-39338 core_question: Make history box a .well
MDL-37968 course_overview: add dim class to hidden courses for teachers.
MDL-40088 fixed bug with not visible course section
MDL-39871 themes: can now specify regions to swap when using rtl langs
MDL-39841 renderer: new method to renderer blocks with predictable structure
MDL-39838 renderer: new methods for body classes and id
MDL-39839 renderer: new methods for  calls appearing in theme layouts
MDL-39824 output: tidied up output before bootstrap cleaning
MDL-40089 theme_bootstrapbase: moved general to columns3.php as prep
MDL-39824 theme_bootstrapbase: converted $PAGE use to new $OUTPUT methods.
MDL-39842 js: fixed block drag and drop