title: When is a device token assigned?
body: <p>I am trying the Urban Airship APNS development push server. When I run their sample app, I can't seem to get the Device Token. What needs to be done to make sure the token exists?
  I've checked the provisioning profile and the bundle id.</p>
  
  <p>Does my server need to push (through UrbanAirship) for the token to be generated for the first time?  Is the token generated at the first push time? How do I register devices to receive push notifications? (I assume that this is built into the sample app, but what do I know...)</p>