Author: Shamim Rezaie
MDL-62318 core_group: Add implementation of privacy API
http://git.moodle.org/gw?p=moodle.git;a=commit;h=9c172adefecca2563452ef16cd746e97a95e79ea
http://github.com/moodle/moodle/commit/9c172adefecca2563452ef16cd746e97a95e79ea
+ 3.3 en [privacy:metadata:groups,core_group]
+ 3.3 en [privacy:metadata:groups:groupid,core_group]
+ 3.3 en [privacy:metadata:groups:timeadded,core_group]
+ 3.3 en [privacy:metadata:groups:userid,core_group]