Author: Sam Hemelryk
MDL-26869 admin: Added page to view admin categories and included in navigation with a new setting
http://git.moodle.org/gw?p=moodle.git;a=commit;h=83f78f8dac061ed3d861daf0b127dce4387ac44b
http://github.com/moodle/moodle/commit/83f78f8dac061ed3d861daf0b127dce4387ac44b
+ 2.3 en [admincategory,core_admin]
+ 2.3 en [linkadmincategories,core_admin]
+ 2.3 en [linkadmincategories_help,core_admin]
+ 2.3 en [categoryerror,core_error]