make track list cells display entire album and artist

[mattneub]

This PR fixes what I regard as iSub's primary shortcoming: in a list of tracks, the track names (i.e. the song titles) are so curtailed as to be useless, especially in the area of my primary listening, classical music. This is what a typical album tracks list looks like now:

After this PR , that same screen looks like this:

As you can see, the full title and artist are now displayed. This change is visible in all places where we displaying individual tracks / songs of an album, but nowhere else; for example, the Songs list and the Playlist (queue) are unaffected. If you're in doubt about the desirability of this for all users, it would be a simple matter to make it a pref that the user can toggle.