Broadcast level loaded event on tech.

[boushley]

This allows consumers to get at custom metadata from the HLS manifest.

[shacharz]

Seems reasonable, let's make it more general:

Object.keys(Hls.Events).forEach(function(key) {
  var eventName = Hls.Events[key];
  hls.on(eventName, function(event, data) {
    tech.trigger(eventName, data);
  });
});

[boushley]

Good point. I've gone ahead and updated this to broadcast all events.