/** Sanitizes value for Get, Post and Cookie
	 * must call ::logValidationWarning if replacing some character(s) that raise security suspicion 
	 * default implementation is no sanitization.  
	 * May be overridden on HttpValidator to do actual sanitization with respect to character encoding and browser issues.
	 * Type-specific sanitization is to be done on StringConverter
	 * @return string sanitized value 
	 * @param string value
	 */
	function sanitizeGpc($key, $value) {
		return $value;
	}