Music & Sound

Hey @thebracket, I'd like to try my hand at implementing some music and sound for this game and tutorial if you don't mind. I figure I can cover 2 of the 3 music/noise scenarios:

1. Ambient music for different levels and stuff - I can create a soundtrack using good ol' 8-bit sounds
2. Sound effects (weapons, spells, etc.) - Use creative-commons resources

Voice editing is the last scenario that is also beyond my resources.

After doing a little bit of research, I think this library [rodio](https://docs.rs/rodio/0.11.0/rodio/) could do most of the heavy lifting. I imagine a light wrapper in RLTK that allows the caller to specify whether they want their sounds to loop (ex. ambient soundtrack on a level) or be played once (such as swords clashing). I would of course write tutorial chapters to teach others how to add sounds to their games.

I am quite new to Rust and would possibly need some help along the way but I think this would be an exciting project to undertake! Let me know what you think :)