self.performSegueWithIdentifier("showApp", sender: self)

class SplashViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        sleep(2)

        // THIS DOES NOTHING:
        self.performSegueWithIdentifier("showApp", sender: self)

        // THIS AS SUGGESTED ALSO DOES NOTHING:
        var otherViewController:UIViewController = self.storyboard.instantiateViewControllerWithIdentifier("test") as UIViewController
        self.presentViewController(otherViewController, animated: true, completion: nil)
    }
}