fix to display filename if tags are missing

willie-mpd

  if ((mpdcommand == 'playing') or (mpdcommand == 'state')) :
    currentsong = client.currentsong()
    currentstatus = client.status()

    if 'artist' in currentsong and 'title' in currentsong:
      nowplaying = currentsong['artist'] + ' - ' + currentsong['title']
    elif 'artist' in currentsong:
      nowplaying = currentsong['artist']
    elif 'title' in currentsong:
      nowplaying = currentsong['title']
    else:
      nowplaying = currentsong['file']


    if currentstatus['state'] == 'play':
      bot.say('Now playing: ' + nowplaying)
    elif currentstatus['state'] == 'pause':
      bot.say('Music is currently paused (' + nowplaying + ')')
    elif currentstatus['state'] == 'stop':
      bot.say('No music is playing')