Check for phpwhois

Hello

A plugin of mine uses phpwhois. A user is using both wordfence and my plugin. This causes problems because both plugins are trying to load php whois classes. Can you please add a check in wordfence::ajax_whois_callback before loading whois.main.php? For example:

public static function ajax_whois_callback(){
		if( ! class_exists( 'Whois' ) ) {
			require_once('whois/whois.main.php');
		}
		$val = trim($_POST['val']);
		$val = preg_replace('/[^a-zA-Z0-9\.\-]+/', '', $val);
		$whois = new Whois();
		$result = $whois->Lookup($val);
		return array('ok' => 1, 'result' => $result);
	}

http://wordpress.org/plugins/wordfence/