Author: Ryan Wyllie
MDL-54698 message: change preferences to on/off text
http://git.moodle.org/gw?p=moodle.git;a=commit;h=efa079072ceda3d16563c4df006e74ae4f0c19ce
http://github.com/moodle/moodle/commit/efa079072ceda3d16563c4df006e74ae4f0c19ce
+ 3.2 en [off,core_message]
+ 3.2 en [on,core_message]