Author: Ankit Agarwal
MDL-32431 backup: Adding the feature to support backing up and restoring calendar events
http://git.moodle.org/gw?p=moodle.git;a=commit;h=1ac84ccdfc2c1a18800283d3bbdf36a1a5539ed9
http://github.com/moodle/moodle/commit/1ac84ccdfc2c1a18800283d3bbdf36a1a5539ed9
+ 2.2 en [rootsettingcalendarevents,core_backup]