Author: Jetha Chan
MDL-48542 user_menu: add proper divider support
Added divider support to the user menu; hardened the custom user menu against invalid input.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=22893d6f4756c82b67d4142fd65d7482987e716b
http://github.com/moodle/moodle/commit/22893d6f4756c82b67d4142fd65d7482987e716b
+ 2.9 en [configcustomusermenuitems,core_admin]