Author: David Mudrak
MDL-20438 send notifications via messaging API
http://git.moodle.org/gw?p=moodle.git;a=commit;h=a77141a7dc0735c6bb5f33850bcc36f19febcdc9
http://github.com/moodle/moodle/commit/a77141a7dc0735c6bb5f33850bcc36f19febcdc9
+ 2.3 en [updateavailabledetailslink,core_admin]
+ 2.3 en [updateavailableforplugin,core_admin]
+ 2.3 en [updatenotificationfooter,core_admin]
+ 2.3 en [updatenotificationsubject,core_admin]
+ 2.3 en [messageprovider:availableupdate,core]