Author: Andrew Davis
gradebook MDL-23433 had another go at the show hidden item help item
http://git.moodle.org/gw?p=moodle.git;a=commit;h=6f4b954af49984532c1eeaa08cdd97797dbed0b4
http://github.com/moodle/moodle/commit/6f4b954af49984532c1eeaa08cdd97797dbed0b4
+ 2.0 en [showallhidden,core_grades]
+ 2.0 en [showhiddenitems_help,core_grades]
+ 2.0 en [shownohidden,core_grades]