add new methods to messages class to let it take care of stash and pop of the messages
update login.php to use new methods
tweak html function to put the $_SESSION['message'] in the stack so there is only one code point to maintain for rendering
Implement new messages class
Support legacy $_SESSION['message_*']
New function messages::add($message, $mood, $delay) to simplify adding messages
updated core/users/user_edit.php to demonstrate
includes space->tab corrections