Remove boilerplate when displaying UIAlertControllers from a UIViewController

UIAlertControllerErrorDisplay

protocol UIAlertControllerErrorDisplay
{
    func showAlertControllerWithError(error:NSError)
}

extension UIViewController:UIAlertControllerErrorDisplay
{
    func showAlertControllerWithError(error:NSError)
    {
        NSOperationQueue.mainQueue().addOperationWithBlock { () -> Void in
            let alert = UIAlertController(title: "Error", message: error.localizedDescription, preferredStyle: .Alert)
            alert.addAction(UIAlertAction(title: "Dismiss", style: UIAlertActionStyle.Default, handler: nil))
            self.presentViewController(alert, animated: true, completion: nil)
        }
    }
}