Skip to end when rewinding

[CreeperPookie]

The loop feature you added in #25 is great; I use it all the time. However, when I want to play a song backwards with loop on, playback stops once it reaches 0. If loop is on, and I'm rewinding, it should do the same thing it would in normal play mode, but go to the end, as I'm playing it in reverse.

[Bentroen]

Makes sense!