MDL-39563 Fixing mobilecssurl is not being returned in WebService get_siteinfo
MDL-40195: mod_assign: Display grades when quickgrading to 2 decimal places
MDL-40538 caching: Use isset for performance

isset is much faster than array_key_exists. For caches we need to
ensure as much performance as possible. To all null to continue to
be stored and provide correct results, non ttl also now saves in
$this->store[$key][0].  As isset($this->store[$key]) will return
true in all cases.

time() as found in cache::now() can be slow on some platforms and
we shouldn't bother checking it unless needed. It also stops non-ttl
caches paying the ttl price.

Unit tests were adjusted to ensure null is still handled correctly
when we are only using isset.
MDL-40621 fixed small bug in function editor_tinymce_plugin::fix_row()
MDL-39563 Fixing mobilecssurl is not being returned in WebService phpunit tests
MDL-38747 blocks: course format options numsections is required to display the block
MDL-40536 course: unit tests for course_external::import_course

Basic import operations and a specific test case which identifies
a bug.
MDL-40536 course/externallib fix incorrect variable

Fixes test_import_course_invalid_deletecontent_option() from the
previous commit.
MDL-40569 fix empty CSS files after cache purging
MDL-40558 skip admins and guest when deleting incomplete users
MDL-40633 filter_urltolink breaking some image links.

This was a regression caused by MDL-22390. HTML like
<img src="http://www.example.com/logo.gif" />
was being broken.
MDL-40611 fix context cache size expectation
MDL-39062 cache: persist keys now set properly
MDL-39062 cache: version bump to update definitions
Automatically generated installer lang files
Merge branch 'wip-MDL-39062-m24' of git://github.com/samhemelryk/moodle into MOODLE_24_STABLE
Merge branch 'MDL-40633_24' of git://github.com/timhunt/moodle into MOODLE_24_STABLE
Merge branch 'MDL-39563-24' of git://github.com/jleyva/moodle into MOODLE_24_STABLE
MDL-39563: Change to use $CFG consistently
Merge branch 'wip-MDL-38747-MOODLE_24_STABLE' of https://github.com/satrun77/moodle into MOODLE_24_STABLE