title: Support for navigator.geolocation change event
body: <p>It would be awesome to be able to attach a listener to a change in geolocation.</p>
  
  <p>I haven't been able to find anything commenting on this either on <a href="http://dev.w3.org/geo/api/spec-source.html" rel="nofollow">w3</a> or searching elsewhere. Seems that its obviously not provided at the moment, but is there any planned support for this from any browser or any w3 spec?</p>