Make microphone icon a bit smaller.
Fall back to naming the merged track "Together"...

Sometimes there are no usable artist names in Singstar's XML files. If
this is the case for a duet track, we call the merged track "Together".

Missing: <TRACK Name="Player1"> </TRACK>
All OK:  <TRACK Name="Player1" Artist="Elton John"> </TRACK>
Fix noteMin and noteMax of combined duet track.