title: Can I listen for GPS changes?
body: <p>I am writing app, that collects location data, based on GPS. And i have next problem:
  when i try to get GPS data and GPS is turned off, i show notification that ask for turning on GPS, and it starts(on click of course) intent with "ACTION_LOCATION_SOURCE_SETTINGS". Question: how can i know that user turned it on? is there some broadcasted actions, or i can set some listener, or something else?</p>