MDL-45982: Implement displaying of non error messages from a provider.
MDL-43347 grades: consistent interface for drop lowest setting
MDL-43347 grades: convert keep highest to text field
Automatically generated installer lang files
MDL-45381 mod_forum: changed event URL for subscription created/deleted events
MDL-16474 scale: Allow scales with 1 item
MDL-46144 core_calendar: Fixed linking of labels on calendar pages
MDL-42393 calendar: Preventing open/close loop in events overlay
MDL-45381 mod_forum: updated unit tests for subscription created/deleted events
Automatically generated installer lang files
MDL-46225 core_admin: Changed heading to add a new user to a button
MDL-43849 mod_forum: Adding tests for observers
MDL-43849 enrol_meta: Renaming methods according to what they test
MDL-46163 question/quiz: fix elements ids and their labels
Merge branch 'install_master' of https://git.in.moodle.com/amosbot/moodle-install
weekly release 2.8dev
MDL-46212 question editing: extra answer fields notice.

It turns out that PHP does not interpret "$field[$key]" the way we were
expecting.
MDL-46212 questions: add {} whenver vars are put into "" strings

Having had one subtle bug cased be this, I decided to do a search and
fix all of these.
MDL-46208 cachestore_mongo: fixed invalid collection name use
MDL-41502 course: removed classes and files deprecated in 2.6