Author: Shamim Rezaie
MDL-60188 groups: cache user's groups and groupings
The function groups_get_user_groups is called too often both before rendering the page and after the page is rendered (using ajax).
The function was executing a query joining 3 tables in each call. The plementation of the function has now modified to store the
query result in a request cache.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=b8e0488c90a1b09b8d720eac9320c61944a664f9
http://github.com/moodle/moodle/commit/b8e0488c90a1b09b8d720eac9320c61944a664f9
+ 3.4 en [cachedef_user_group_groupings,core_cache]