title: GCM 3.0 - can you override Android notifications delivered via notification payload (not data payload)
body: <p>Can you override an incoming GCM 3.0 Android notification delivered via a notification payload (not data payload)? </p>
  
  <p>For example, to let the user the user disable notifications of a certain type. Obviously this is easily done with the data payload, but I would like to do it via the notification payload if possible.</p>
  
  <p>Also, I think the <code>icon</code> json field only sets the <code>smallIcon</code> in a notification. Is this any more customizable without using the data payload?</p>