MDL-44124 libraries: Allow rrules with only one part during rrule validation checks
MDL-46013 theme: Uninstall theme unconditionally unsets configs
MDL-43835 phpunit: Create unique starting id's for sequences.

When all starting autoincrement ids are the same, it's difficult to detect coding and testing
errors that use the incorrect id in test calls.  The classic case is cmid vs instance id.
To reduce the chance of the coding error we start sequences at different values where possible.

OUBlog installation is the case that highlighted this as it inserts a sitewide course module
at install time and cmid <> instance id in most cases.
MDL-43835 phpunit: Correct unit tests.

When different ID's are set for each sequence a number
of unit test failures appear.  They have been corrected
to allow unit tests to pass with the new generator in place.
MDL-46086 quiz: fix unit test on Oracle
MDL-35453 quiz reports: don't order by id.

We were using ORDER BY id even though there was a perfectly good
attempt column to order the attempts by one user at one quiz.

Also, Oracle was complaining:
Debug info: ORA-01799: a column may not be outer-joined to a subquery
MDL-41746 External api: Allow multiple calls to validate_context at different levels

(Only from webservices)
MDL-38693 themes: amended z-indexes

Amended #dock z-index level from 11000 to 5000 across all themes; amended z-index style of #page-header in Overlay theme such that elements no longer occlude TinyMCE.
MDL-37145 caching: noted recommendation for dedicated memcache servers

Several reports have been made about the unexpected purging of entire
memcached servers when MUC is configured to use Memcache and caches
get purged.
This is expected and occurs because the memcache extenions don't
provide isolated containers. Moodle data is stored along side any other
data in the cache and when caches get purged all data gets removed
whether it belongs to Moodle or not.

The docs cover this point and here I've added notes about this to both
config-dist.php and cache/README.md
MDL-45580 assignfeedback_editpdf: Store a readonly version of the PDF
MDL-45580 assignfeedback_editpdf: Delete draft content on new submission
MDL-45580 assignfeedback_editpdf: Save readonly version in backup
MDL-45764 mod_lti: Fix adding General Tool

This error only occurs when a ltisource
plugin is present that implements the
get_types callback.
MDL-45958 courselib: Refactor module duplication code to remove duplication
MDL-39883 events: Create a new api create_from_cm for module create event
MDL-39883 events: Trigger a module created event when duplicating a module
MDL-45721 core_backup: only trigger the course_restored event when restoring a course
MDL-44773 atto_accessibilitychecker: Set focus on clicked  warnings
MDL-44773 atto_accessibilitychecker: Improved image test coverage
MDL-44512 themes: fix for custom menu submenu arrows on RTL languages