Helen Foster authored Nov 19, 2018 and David Mudrák committed Nov 19, 2018

Significant string changes:

* courseoverviewfiles, courseoverviewfiles_help, courseoverviewfilesext
  in core, configcourseoverviewfilesext, configcourseoverviewfileslimit
  in core_admin, areacourseoverviewfiles in core_repository - renaming
  of 'Course summary files' to 'Course image'