Author: Huong Nguyen
MDL-4188 core: Added course welcome message notification
http://git.moodle.org/gw?p=moodle.git;a=commit;h=1593f02492e68522ddaa8c9448cd5e113d6eeb40
http://github.com/moodle/moodle/commit/1593f02492e68522ddaa8c9448cd5e113d6eeb40
+ 4.4 en [messageprovider:enrolcoursewelcomemessage,core]