Optional delay / pause between playlast items or loop replay

Add option to have a delay between tracks, both when playing a playlist, and when playing one track in a loop. Allow the user to define the length of the delay in seconds / milliseconds.

• Make sure the user can see the difference between playback having stopped at the end of the playlist, or having to wait for the delay. He should mistake a delay for the end of the playlist, and get surprised after a few seconds when VLC continues. Possibly show a countdown somewhere, or some other visual cue.