Author: Dan Poltawski
MDL-51651 lang: the first day of the week is Monday
http://git.moodle.org/gw?p=moodle.git;a=commit;h=b340da9420e790c137e8b5eb16ce95cda625540f
http://github.com/moodle/moodle/commit/b340da9420e790c137e8b5eb16ce95cda625540f
+ 2.9 en [firstdayofweek,core_langconfig]