title: Argument labels '(URL:)' do not match any available overloads
body: <p>I'm trying to convert my code to Swift 3 and I get this error:</p>
  
  <blockquote>
    <p>Argument labels '(URL:)' do not match any available overloads</p>
  </blockquote>
  
  <pre><code>let viewController = VisitableViewController(URL: URL)
  </code></pre>
  
  <p>Here is my entire code:</p>
  
  <pre><code>var window: UIWindow?
  var navigationController = UINavigationController()
  var session = Session()
  
  
  func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -&gt; Bool {
      window?.rootViewController = navigationController
      visit(URL: NSURL(string: "http://localhost:9292/")!)
      return true
  }
  
  func visit(URL: NSURL) {
      let viewController = VisitableViewController(URL: URL)
      navigationController.pushViewController(viewController, animated: true)
      session.visit(viewController)
  }
  </code></pre>
  
  <p>Here is the VisitableViewController :</p>
  
  <pre><code>import UIKit
  
  open class VisitableViewController: UIViewController, Visitable {
      open weak var visitableDelegate: VisitableDelegate?
  
      open var visitableURL: URL!
  
      public convenience init(url: URL) {
          self.init()
          self.visitableURL = url
      }
  
      // MARK: Visitable View
  
      open private(set) lazy var visitableView: VisitableView! = {
          let view = VisitableView(frame: CGRect.zero)
          view.translatesAutoresizingMaskIntoConstraints = false
          return view
      }()
  
      fileprivate func installVisitableView() {
          view.addSubview(visitableView)
          view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|[view]|", options: [], metrics: nil, views: [ "view": visitableView ]))
          view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|[view]|", options: [], metrics: nil, views: [ "view": visitableView ]))
      }
  
      // MARK: Visitable
  
      open func visitableDidRender() {
          self.title = visitableView.webView?.title
      }
  
      // MARK: View Lifecycle
  
      open override func viewDidLoad() {
          super.viewDidLoad()
          view.backgroundColor = UIColor.white
          installVisitableView()
      }
  
      open override func viewWillAppear(_ animated: Bool) {
          super.viewWillAppear(animated)
          visitableDelegate?.visitableViewWillAppear(self)
      }
  
      open override func viewDidAppear(_ animated: Bool) {
          super.viewDidAppear(animated)
          visitableDelegate?.visitableViewDidAppear(self)
      }
  
      /*
       If the visitableView is a child of the main view, and anchored to its top and bottom, then it's
       unlikely you will need to customize the layout. But more complicated view hierarchies and layout 
       may require explicit control over the contentInset. Below is an example of setting the contentInset 
       to the layout guides.
  
      public override func viewDidLayoutSubviews() {
          super.viewDidLayoutSubviews()
          visitableView.contentInset = UIEdgeInsets(top: topLayoutGuide.length, left: 0, bottom: bottomLayoutGuide.length, right: 0)
      }
      */
  }
  </code></pre>