Author: Andrew Davis (andyjdavis)
MDL-22232 messaging: reimplementing support for "emailstop" in 2.0 stable
http://git.moodle.org/gw?p=moodle.git;a=commit;h=bec1c29d84a4b6761d139d17935c9f026e7e0450
http://github.com/moodle/moodle/commit/bec1c29d84a4b6761d139d17935c9f026e7e0450
+ 2.0 en [disableall,core_message]
+ 2.0 en [disableall_help,core_message]