Author: Bas Brands
MDL-63445 core_renderer: display course image in context header
http://git.moodle.org/gw?p=moodle.git;a=commit;h=a7712a985196eaa73dedb28c7a2e33cf848babc5
http://github.com/moodle/moodle/commit/a7712a985196eaa73dedb28c7a2e33cf848babc5
+ 3.6 en [courseheaderimage,core]
+ 3.6 en [showcourseimages,core]
+ 3.6 en [showcourseimages_desc,core]