Author: Anastasios Bithas
MDL-22570 group: Export groups/groupings to ods/xls/txt
A new feature that enables teachers to export groups and
groupings through the groups overview page, making use of the dataformat api.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=3df0908e726d78105b377953f2008abba7740aa4
http://github.com/moodle/moodle/commit/3df0908e726d78105b377953f2008abba7740aa4
+ 4.1 en [exportgroupsgroupings,core_group]