title: JSQMessageAvatarImageFactory error
body: <p>For some reason I am getting an crash and I am not sure why. Everything is being pulled from FIRBase correctly. But when trying to load the user url I get a crash</p>
  
  <p>printed(snapshot)</p>
  
  <pre><code>["MediaType": TEXT, "text": Test Message, "senderId": KG7b3tDTaoMwcAQAi2JI8vjj0OB2, "senderName": user1]
  Optional({
  email = "user1@gmail.com";
  id = KG7b3tDTaoMwcAQAi2JI8vjj0OB2;
  profileImage = "gs://big-pen.appspot.com/profileImage/KG7b3tDTaoMwcAQAi2JI8vjj0OB2";
  username = user1;})
  </code></pre>
  
  <p>My error</p>
  
  <pre><code>fatal error: unexpectedly found nil while unwrapping an Optional value
  (lldb) 
  </code></pre>
  
  <p>Here is my code.</p>
  
  <pre><code>func observeUsers(id: String){
         FIRDatabase.database().reference().child("people").child(id).observeEventType(.Value, withBlock: { snapshot in
          print(snapshot.value)
          if let dict = snapshot.value as? [String: AnyObject] {
              let avatarUrl = dict["profileImage"] as! String
  
              //call the setupAvatar function
              self.avatar(avatarUrl, messageId: id)
  
          }
      })
  }
  
  
  func avatar(url: String, messageId: String){
  
      if DataService.dataService.currentUser != nil{
          if url != "" {
          let fileURL = NSURL(string: url )
          let data  = NSData(contentsOfURL: fileURL!)
          let image = UIImage(data:data!)  //&lt;-----I am getting an error at this line error code: "Thread1:EXC_BAD_INSTRUCTION(code=Exc_I386_INVOP, subcode=0x0)"
          let userImg = JSQMessagesAvatarImageFactory.avatarImageWithImage(image, diameter: 30)
              avatarDict[messageId] = userImg
          }else{    
          JSQMessagesAvatarImageFactory.avatarImageWithImage(UIImage(named: "cam_w.png"), diameter: 30)
      }
      collectionView.reloadData()
      }
  }
  
  override func collectionView(collectionView: JSQMessagesCollectionView!, avatarImageDataForItemAtIndexPath indexPath: NSIndexPath!) -&gt; JSQMessageAvatarImageDataSource! {
      let message = messages[indexPath.item]
  
      return avatarDict[message.senderId]
      //return JSQMessagesAvatarImageFactory.avatarImageWithImage(UIImage(named: "cam_w.png"), diameter: 30)
  }
  </code></pre>
  
  <p>Thanks. I have been stuck on this for two days now.</p>