Author: Damyon Wiese
MDL-58219 googledocs: Use a cache
Speed up folder operations with a simple cache.
Part of MDL-58220
http://git.moodle.org/gw?p=moodle.git;a=commit;h=39f60f6c008a34f387f929ea3036f2b6171e2eb8
http://github.com/moodle/moodle/commit/39f60f6c008a34f387f929ea3036f2b6171e2eb8
+ 3.3 en [cachedef_folder,repository_googledocs]