Notification of string changes

Author: Petr Skoda
MDL-16640 do not show login form to users that are already logged in, this may solve some sesskey problems caused by re-logging


http://git.moodle.org/gw?p=moodle.git;a=commit;h=e81fb5efad2272d0fc4f23938a6df40dd25ca05f
http://github.com/moodle/moodle/commit/e81fb5efad2272d0fc4f23938a6df40dd25ca05f

+ 2.0 en [alreadyloggedin,core_error]