We should indicate the API changes for developers.

Return active filters in core_course_get_courses_by_field

Right now this WS is returning all the sections without advising if is
a stealth section or not, this have some implications (in the mobile
app right now the stealth sections are displayed)

- New site setting to define the default course duration (used to set
  the default end date for some course formats)
- End date setting out of restore
- Fix tool_uploadcourse
- Other fixes here and there

Frederic Massart authored Sep 01, 2016 and Dan Poltawski committed Sep 23, 2016

Part of MDL-55071

This commit reduces boilerplate code.
It also forces WS returning files to always return the following
fields: filename, filepath, mimetype, filesize, timemodified and
fileurl.