I don't like the Interface Builder. In Xcode 5 people like me could chose the empty project template. This template was meant to be used in projects without xibs or storyboards. In Xcode 6 this template is gone. So let's use one of the given templates and remove the storyboard.

Start Xcode and create a new project. In the template chooser select the Single View Application template.

templateChooser

Give it a name an a place to be stored. Then remove the storyboard.

removeStoryboard1

Remove the storyboard in the Deployment Info of you Target (delete the "Main" in the "Main Interface" drop down; leave it empty).

removeStoryboard2

Initialize the window and make it key and visible in the application delegate.

func application(application: UIApplication!, didFinishLaunchingWithOptions launchOptions: NSDictionary!) -> Bool {
        window = UIWindow(frame: UIScreen.mainScreen().bounds)
        
        window!.rootViewController = ViewController(nibName: nil, bundle: nil)
        window!.makeKeyAndVisible()
        window!.backgroundColor = UIColor.whiteColor()
        return true
    }

Done. Enjoy the clean and pure code project.