title: Notification with sound although phone is muted
body: <p>I am creating a notification with Android's NotificationManager.</p>
  
  <p>Is it possible to 'override' the phone's volume (mute) settings in such a way, that the notification's sound is ALWAYS played?</p>
  
  <p>The reason I need this is the following:
  The notification is so important, that vibration alone may not be enough. The user MUST be alerted. So a sound shall be played, even if the phone is muted or the volume is very low.</p>