Author: Ankit Agarwal
MDL-36621 calendar: Ical event should display source info
http://git.moodle.org/gw?p=moodle.git;a=commit;h=8a7326ed4ee589338a2cd6444f681ae7570e9a0d
http://github.com/moodle/moodle/commit/8a7326ed4ee589338a2cd6444f681ae7570e9a0d
+ 2.5 en [subsource,core_calendar]