Author: Tony Butler
MDL-49582 core_lib: Add button to allow user to reset table preferences
http://git.moodle.org/gw?p=moodle.git;a=commit;h=bf7c844e941df51d3bfd4768f24ca4ee8a72e6fe
http://github.com/moodle/moodle/commit/bf7c844e941df51d3bfd4768f24ca4ee8a72e6fe
+ 3.0 en [resettable,core]