Author: Marina Glancy
MDL-60742 calendar: allow customisation of 12/24h time format strings
http://git.moodle.org/gw?p=moodle.git;a=commit;h=099bca6de616912f5a60c399e68280ca90e163c1
http://github.com/moodle/moodle/commit/099bca6de616912f5a60c399e68280ca90e163c1
+ 3.5 en [strftimetime12,core_langconfig]
+ 3.5 en [strftimetime24,core_langconfig]