title: WKWebView Content loaded function never get called
body: <p>i try to get a function called after my Content inside WKWebView is fully loaded. I found the "didFinishNavigation" function at the Apple Swift WKNavigation Documentation.</p>
  
  <pre><code>func webView(webView: WKWebView!, didFinishNavigation navigation: WKNavigation!) {
      println("WebView content loaded.")
  }
  </code></pre>
  
  <p>But the function never get called. </p>
  
  <pre><code>import UIKit
  import WebKit
  
  class ViewController: UIViewController WKNavigationDelegate {
  
     override func loadView() {
         super.loadView()
  
         self.webView = WKWebView(frame:self.containerView.frame, configuration: WKWebViewConfiguration())
         self.containerView.addSubview(webView!)
         self.containerView.clipsToBounds = true
  
     }
  
     override func viewDidLoad() {
         super.viewDidLoad()
  
         var url = NSURL(string:"http://google.com/")
         var req = NSURLRequest(URL:url)
         self.webView!.loadRequest(req)
     }
  
     func webView(webView: WKWebView!, didFinishNavigation navigation: WKNavigation!) {
         println("WebView content loaded.")
     }
  
  }
  </code></pre>