Author: Ankit Agarwal
MDL-22895 backup: Adding the feature to support backing up and restoring calendar events
http://git.moodle.org/gw?p=moodle.git;a=commit;h=8331a159c58031bdbbb25fa5ec87102f2f66631c
http://github.com/moodle/moodle/commit/8331a159c58031bdbbb25fa5ec87102f2f66631c
+ 2.3 en [rootsettingcalendarevents,core_backup]