MDL-44451 fix plugin_misplaced_exception exception
MDL-44345 repository_youtube: Endless loop when reaching last results
MDL-43721 Assign: Static cache for plugin is_enabled and is_visible because they get used alot
MDL-43721 Assign + groups: Improve performance of assign grading table

Add a function to the groups lib to filter a list of users down
to the ones who can see the module. Required because calling
groups_course_module_visible() for a list of users is too slow
and we shouldn't spread group logic outside of grouplib.php.

Using it in the assign grading table reduces DB queries from 6198/1 to 256/3.

This is 12secs down to 2.5secs.

Conflicts:
	mod/assign/locallib.php
MDL-44480 Javascript: Correct dialogue ID generation
MDL-32699 wiki: only edit capability is required to restore wiki revision
MDL-40721 wiki: missing page->set_url() when restoring wiki
MDL-44337 glossary: behat test for glossary categories
MDL-42870 completion: show failed activities as incompleted
MDL-42368 Themes: Anomaly breadcrumb fix

Previously the editing button could become unreachable with small window
sizes.
Moodle release 2.5.5
MDL-37733 SCORM: Correct check for force new attempt
MDL-43236 behat: Backporting new method to ease backporting future scenarios
Merge branch 'MDL-43236_25' of git://github.com/dmonllao/moodle into MOODLE_25_STABLE
Merge branch 'MDL-43721-25' of git://github.com/damyon/moodle into MOODLE_25_STABLE
MDL-44547 repository_alfresco: version bump
Merge branch '44547-25' of git://github.com/samhemelryk/moodle into MOODLE_25_STABLE
Merge branch 'w11_MDL-44451_m25_addonloc' of https://github.com/skodak/moodle into MOODLE_25_STABLE
Merge branch 'wip-MDL-40721-m25' of git://github.com/marinaglancy/moodle into MOODLE_25_STABLE
Merge branch 'wip-MDL-42870-m25' of git://github.com/marinaglancy/moodle into MOODLE_25_STABLE