<system>:last-music-item: initialize when at -1.  Fixes finding last==first.
<system>:last-music-item: initialize when at -1.  Fixes finding last==first.

janneke/schikkers-list,janneke/schikkers-list,janneke/schikkers-list,janneke/schikkers-list,janneke/schikkers-list