Should zero-out play progress upon intent to play next track

[rtlong]

After clicking a new track to play, play progress bar and times don't zero-out until new track is found and begins streaming

[rtlong]

Another, probably better approach is not to stop playing the current track until we're ready to start the next one, which would likely mean adding a second <audio> element and at that point we're all set to start cross-fading between tracks, as well, which would be cool