title: UIActivityViewController Subject not working for Outlook
body: <p>Foe setting subject of share, overriding </p>
  
  <pre><code>   func activityViewController(activityViewController: UIActivityViewController, subjectForActivityType activityType: String?) -&gt; String {
            return "mySubject"
      }
  </code></pre>
  
  <p>not working for outlook app, while sharing. this method not being called for outlook, works for other apps like mail, gmail etc.</p>
  
  <p>Found that some app like Yelp, Apple maps, Google Maps able to set subject in outlook. How'd one achieve it?</p>