Fixed vanilla r713

In revision 714, I am adding a method to the session class to retrieve the key. It create the session key if needed and make the getting the key easier.:

/**
* Return the key used for CSRF protection.
* @return String
*/
function GetCsrfValidationKey() {
$Key = $this->GetVariable('SessionPostBackKey', 'string');
if ($Key == '') {
$Key = DefineVerificationKey();
$this->SetVariable('SessionPostBackKey', $Key);
}
return $Key;
}

Vanilla r714, People r98, Framework r153