MDL-39286 Remove link on My Courses settings heading
MDL-41446 Completion: Incorrectly marks complete when grade data present with no actual grade
MDL-40939 tex filter: Changes to the TeX notation plugin

- Added configurable setting for path to mimetex binary
- Moved language strings from lang/en/admin.php to lang/en/filter_tex.php
- Config settings now stored in table config_plugins and retrieved
through get_config
- Added upgrade step to move TeX settings to the config_plugins table
and delete settings from the config table

AMOS BEGIN
  MOV [configconvertformat,core_admin],[configconvertformat,filter_tex]
  MOV [convertformat,core_admin],[convertformat,filter_tex]
  MOV [latexpreamble,core_admin],[latexpreamble,filter_tex]
  MOV [latexsettings,core_admin],[latexsettings,filter_tex]
  MOV [pathconvert,core_admin],[pathconvert,filter_tex]
  MOV [pathdvips,core_admin],[pathdvips,filter_tex]
  MOV [pathlatex,core_admin],[pathlatex,filter_tex]
AMOS END
MDL-32888 Grader report: added user search
MDL-32888 Grader report: refined user search
MDL-32888 Grader report: refined user search with no reset
MDL-32888 Grader report: cater for suspended students
MDL-32888 Grader report: use SESSION object and DB functions
MDL-32888 Grader report: Refined SESSION and api function use
MDL-42573 skydrive: support non-js login scheme

This is actually not especially useful because Microsoft don't currently
support non-JS login. But its possible they could make it work in
future. And at least the user gets an error from MS rather than blank
screen.
MDL-42598 quiz variant randomisation not random enough.

A student would get the same question variants (for example for a
calculated question) on their first attempt at both copies of a
duplicated quiz.
MDL-33536 navigation: hide hidden categories from the navbar
MDL-42215 lang: improved the help string for fullnamedisplay
MDL-40481 quiz responses report needs cols need text_sorting
MDL-42672 blocks: warnings on /mod/xxx/index.php for frontpage course
MDL-42723: Hide and handle LDAP error when user not in context being checked

MDL-41304 only fixed the case when 'Search subcontext' is enabled. We need to
fix the case when it's not enabled too.

While silencing errors with an @ should be avoided if possible, there's no
other way to prevent the warnings in this case.
MDL-42084 Core: Create new static class for use instead of set_time_limit
MDL-42084 Backup: Update time limit to avoid regression, use new class
MDL-42084 Core: Change set_time_limit to core_php_time_limit::raise everywhere

Exceptions (places where set_time_limit is still left) are:

Third-party libraries:
  ADODB
  PHPMailer

Moodle core:
  PHPUnit - not relevant (CLI mode)
MDL-42084 Unit tests: Remove unnecessary 'clear time limit change' lines