How to test drive view in iOS

Issue #303

Instead of setting up custom framework and Playground, we can just display that specific view as root view controller

window.rootViewController = makeTestPlayground()

func makeTestPlayground() -> UIViewController {
    let content = UserCell()
    content.nameLabel.text = "Thor"
    content.streetLabel.text = "Asgard"
    content.weaponLabel.text = "Hammer"

    let viewController = UIViewController()
    viewController.view.backgroundColor = .white
    viewController.view.addSubview(content)

    NSLayoutConstraint.on([
        content.centerXAnchor.constraint(equalTo: viewController.view.centerXAnchor),
        content.centerYAnchor.constraint(equalTo: viewController.view.centerYAnchor),
        content.widthAnchor.constraint(equalTo: viewController.view.widthAnchor, multiplier0.9),
        content.heightAnchor.constraint(equalToConstant: 200)
    ]
    return viewController
}