[session] move context manager logic in the security context manager
The `init_security` and `reset_security` method have no other user that the context manager itself. Having dedicated public function is not useful.
$(document).ready(function() {
$('a.rhythm').click(function (event){
$('div#pageContent').toggleClass('rhythm_bg');
$('div#page').toggleClass('rhythm_bg');
event.preventDefault();
});
});