This files describes API changes for course formats

Overview of this plugin type at http://docs.moodle.org/dev/Course_formats

=== 3.6 ===
* New method validate_format_options() cleans the values of the course/section format options before inserting them
  in the database. Course format options can now be set in tool_uploadcourse and validation of user-submitted data is important.
  Note that validate_format_options() is now always called when somebody creates or edits course or section and also
  during restore and course upload. Default implementation validates against the definition of the form elements for
  format options.
* The final deprecation of xxx_delete_course callback means that this function will no longer be called.
  Please use the observer for event \core\event\course_content_deleted instead.

=== 3.5 ===
* Course formats should overwrite get_config_for_external function to return the course format settings viewable by the
  current user.
  If the course format does not have any setting that could be considerated private (like a private/access key/token),
  is ok to return all the settigns via the get_format_options function.

=== 3.3 ===
* Javascript code for editing activities and sections was moved to an AMD module, course/rest.php is no longer
  responsible for editing actions, instead it is done in web services. Carefully test all editing actions during upgrade.
* The new method format_base::allow_stealth_module_visibility() can indicate whether course format supports "stealth"
  activities mode when they are available but not visible on course page. Course format that supports stealth mode
  must check $cm->is_visible_on_course_page() when displaying activities list on the course page instead of $cm->uservisible.
  For all other plugins except course formats the same property $cm->uservisible indicates if the activity contents
  is actually available to student.
* Option "Number of sections" (numsections) was removed from topics and weeks formats, instead the actual number of records
  in the course_sections table is treated as a number of sections (excluding section 0 that should always be present).
* Method create_course() will populate the new course with empty sections if $data->numsections is provided even if
  "numsections" is not an option defined by the course format.
* course/changenumsections.php can now be used to insert sections at any positions.
* The variable SECTIONLEFTSIDE was changed from '.left .section-handle img' to '.left .section-handle .icon' in
  course/format/topics/format.js and course/format/weeks/format.js due to the introduction of Font Awesome (see MDL-40759)
  which altered the HTML. Please check if your course format relies on this selector, and if so, update it.

=== 3.2 ===
* Callback delete_course is deprecated and should be replaced with observer for event \core\event\course_content_deleted
* Course formats can overwrite get_default_course_enddate function to set the default course end date for new courses.
  format_base::get_default_course_enddate uses the new "Course duration" site setting to calculate the default course end date
  from the default course start date.
* New method format_base::supports_news() which is used to determine whether an Announcements forum will be automatically created on
  course creation. For course format plugin developers, please override format_base::supports_news() to return true if you want the
  Announcements forum to be created upon course creation and remove the block names defined in format_base::get_default_blocks().

=== 3.1 ===
* Course format may use the inplace_editable template to allow quick editing of section names, see
  https://docs.moodle.org/dev/Inplace_editable and MDL-51802 for example implementation.

=== 3.0 ===
* Course formats should now use section_edit_control_items and use the returned array of controls items and their attributes to create a
  renderable menu or array of links.  Plugin calls to section_edit_controls will now include the section edit control in the returned array.
* The section name is now wrapped in a new span (.sectionname > span), process_sections method in format.js should be updated so .sectionname
  DOM node's wraps the section title in a span. You can look at how to implement the change in course/format/topics/format.js or MDL-48947.
* New method format_base::get_default_section_name retrieves the default section name for the given course format. The base
  implementation basically uses the implementation of format_base::get_section_name. The method can be overridden in
  format_base subclasses that use sections (i.e. format_topics, format_weeks). In relation to the changes made for the default
  section name, the default section name is now being shown when editing the section information.

=== 2.9 ===
* Course formats may support deleting sections, see MDL-10405 for more details.
  format_section_renderer_base::section_edit_controls() is now also called for
  stealth sections and it also returns "delete" control.

=== 2.8 ===
* The activity chooser now uses M.course.format.get_sectionwrapperclass()
  to determine the section selector, rather than a hard-coded `li.section`.
* Activity duplication in /course/modduplicate.php is deprecated and is now done in /course/mod.php.  Deprecated calls will be honored by
  redirecting to /course/mod.php for 3rd party plugin support.
* New method format_base::section_get_available_hook() allows plugins to override section availability.

=== 2.7 ===
* The ->testedbrowsers array no longer needs to be defined in supports_ajax().
* format_section_renderer_base::section_hidden has an new second optional argument $courseorid.
  If provided the section name is printed in the not available string when displaying the hidden section.

=== 2.6 ===

* core_course_renderer::course_section_cm_edit_actions has two new optional arguments and now uses and action_menu component.
* core_course_renderer::course_section_cm has been altered to call core_course_renderer::course_section_cm_edit_actions with the two new arguments
* An additional course renderer function has been created which allows you to
  specify the wrapper for a course module within a section (e.g. the <li>).  This can be
  found in core_course_renderer::course_section_cm_list_item().

=== 2.5 ===

* Functions responsible for output in course/lib.php are deprecated, the code is moved to
  appropriate renderers: print_section(), print_section_add_menus(), get_print_section_cm_text(),
  make_editing_buttons()
  See functions' phpdocs in lib/deprecatedlib.php
* Function get_print_section_cm_text() is deprecated, replaced with methods in cm_info

=== 2.4 ===

Course format API has been changed significantly. Instead of implementing callbacks course formats
may overwrite the class format_base. See format_legacy class for a template for upgrading course
format.

* Function settings_navigation::add_course_editing_links() is completely removed, course format
  functions callback_XXXX_request_key() are no longer used (where XXXX is the course format name)
* functions get_generic_section_name(), get_all_sections(), add_mod_to_section(), get_all_mods()
  are deprecated. See their phpdocs in lib/deprecatedlib.php on how to replace them
* Course formats may now have their settings.php file as the most of other plugin types
* Function format_section_renderer_base::is_section_current() is deprecated, overwrite/use
  function is_section_current in format class

=== 2.3 ===

* The new $course->coursedisplay option was introduced, users can now choose to display
  a section at a time if the course formats support it:
 - COURSE_DISPLAY_SINGLEPAGE indicates the teacher has chosen to display all sections on one page
 - COURSE_DISPLAY_MULTIPAGE indicates the teacher has chose to have seperate pages with each section.

* The parameter for 'currently active section' was standardised in core:
  - The course format is passed the currently live section through the $displaysection varaible to format.php
  - A 'section' paramter is the standardised way to pass around the current section in a course
  - Navigation no longer looks for custom parameters defined in callback_format_request_key
