title: iOS 8 share extension doesn't work with iBooks
body: <p>I try to share selected/highlighted text in iBooks with my custom extension, but it doen't have anything inside <code>self.extensionContext</code></p>
  
  <pre><code>&lt;NSExtensionContext: 0x17541d90&gt; - UUID: &lt;__NSConcreteUUID 0x1765e860&gt; D69F0393-C5F1-4DEB-9A97-B479C2BC0C95 - _isHost: NO
  items:
  (
  )
  </code></pre>
  
  <p>so after i choose my extension in provided list it just pops up empty <code>SLComposeServiceViewController</code></p>
  
  <p>Mail, iMessages, Twitter etc. works as expected. Is there any additional magic i must do to handle this?</p>