MDL-41071 core: plugininfo_mod caches in plugininfo_mod definition
MDL-41112 fix theme and js caching info in config-dist.php
MDL-41122: Trim on RSS body to prevent Remote RSS block from failing on valid feeds
MDL-41157 calendar: add unit tests for calendar_get_course_cached
MDL-41157 calendar: improve calendar_get_course_cached

The function get_course() introduced in 2.5.1 will use $COURSE and
$SITE to avoid an uncessary DB query, simplifying the logic of this
function and improving perf.
MDL-41191 forum: unit tests for forum_get_courses_user_posted_in
MDL-41191 enrol: unit tests for enrol_get_shared_courses
MDL-27595 backup: allow course import with warnings
Proceed with import if warnings are found, but display the warnings afterwards
MDL-40896 Add missing question edit CSS to bootstrapbase.
MDL-41036 Question category info should use HTML editor

This is a minimal fix. All this code could do with a clean-up, but at
the moment, it works, so I am not going to touch it.
MDL-41093 qtype match: unique index upgrade problem.

Eliminate duplicate rows before we try to add a unique index. We
arbitrarily keep the duplicate row with the lowest id.
MDL-41162 quiz view page: invalid HTML.

We were sometimes outputting nested p tags. Change the outer one to a
div.
MDL-40830 Clear course cache in mod_assign generator
MDL-36789 Quick course cache integrity check for deleted modules
MDL-39980 question engine: Attempt on last loses response files

When doing Each attempt builds on last, we need to copy any response
files into a draft file area, and then re-save them.

While writing the unit test for this, I had to deal with a todo in the
question engine so that questions with files in the response could be
unit-tested.

I also found an fixed a bug with qtype_essay_question::is_same_response
and fixed some notices in the existing essay/manual graded unit tests.
MDL-38203 multianswer qtype: feedback pop-up should be constrained.

So that, when there is a lot of feedback, it is all visible.
MDL-32191 navigation: Add keys to module and block settings nav nodes
MDL-37393 SCORM: Fixed PHP Strict Standards errors with AICC packages
MDL-37393 SCORM: Fix existing AICC scoes to use correct parent/child relationships
MDL-41144 enrol_flatfile: ignore deleted users.