title: UIApplication.sharedApplication() is unavailable
body: <p>I just upgraded from XCode 6.4 to Xcode 7 GM and get started to change the code to be compliant with Swift 2. I could not come over the following errors.</p>
  
  <p>The project is a keyboard extension and the snippet is from the containing app. </p>
  
  <pre><code>    let s = "https://itunes.apple.com/"
      UIApplication.sharedApplication().openURL(NSURL(string : s)!)
  </code></pre>
  
  <p>Error 1: 'sharedApplication()' is unavailable: Use view controller based solutions where appropriate instead.</p>
  
  <p>Error 2: 'openURL' is unavailable.</p>
  
  <p>This might be something to do with Xcode and AppDelegate, I might have screwed up my project.</p>