MDL-47466 calendar: use get_in_or_equal() in function calendar_get_events to fix problem with ORA-01795
MDL-46531 editor_atto: Color plugins should use classes rather than hardcoded colours
MDL-47466 calendar: fixed error ORA-01795 in calendar_get_events
MDL-47777 assign: max files hard coded to setting

The current file submission is hard coded to a maximum of 20 files
possible.  While the user can choose a number less than 20, the maximum
is still set in code.  This converts the hard coded 20 to a site setting
defaulting to 20.
MDL-36874 mod_book: Add uarrow() output renderer.

In preparation for Book navigation improvements in MDL-36874, this commit
adds a uarrow() output renderer, to complement rarrow() and larrow().
MDL-47930 mod_forum: Display all forum statuses correctly

It is possible for users with the mod/forum:managesubscriptions to
subscribe to forums with subscription disabled. This is handled by
forum_get_subscribe_link() already and should have been handled here all
along.
MDL-36874 mod_book: Add text navigation.

Based on a patch by Matthew Cannings, this replaces Book's previous/next arrow
image links with a choice of: no links, image links, or chapter title text links.
MDL-47793 assign: Reset reveal identities
MDL-47390 mod_forum: Add discussion unsub to email footer
MDL-46500 filepicker: prevent error when element does not exist
MDL-46500 mod_data: Removing duplicate filemanager initialisations
MDL-47990 qtype_multichoice: fix test response import/export
MDL-47390 mod_forum: Correct check for groups when subscribing
MDL-47975 assign: Stop gap fix for random time fails.
MDL-47981 Grade single view: Prevent nasty scroll jumping.
MDL-47982 gradebook: Remove tabindex from all elements.
MDL-46262 availability: validation of fields without value

Thanks to Tomasz Pawlik | CKO USl for the patch
MDL-47874 dml: add support for replace_all_text to oracle

And, at the same time, fix the implementation so all databases
will be using sql_substr() instead of harcoded "SUBSTRING".
MDL-48025 user: fixed typo in user_search HTML
MDL-48026 output: action_menu no wrap improvement

Action menu output component has a new method set_nowrap_on_items
that sets a property to toggle nowrap on menu items.
That can be used to avoid problems when the menu appears within
an absolutely positioned or floated element.