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=a66195b8b95917f45973fd30227e76c5e2fa6f25
http://github.com/moodle/moodle/commit/a66195b8b95917f45973fd30227e76c5e2fa6f25
+ 3.4 en [strftimetime12,core_langconfig]
+ 3.4 en [strftimetime24,core_langconfig]