Asset cleanup, playing around with hot-swapping music

src/audio.rs

@@ -36,6 +36,7 @@ impl Plugin for AudioPlugin {
             (
                 play_audio.run_if(any_component_added::<AudioSource>),
                 audio_trigger.run_if(on_event::<AudioEvent>()),
+                // play_background.run_if(on_event::<AssetEvent<AudioSettings>>()), TODO: Handle music hot-reload
             ),
         );
     }