Use Amiga sound files

[joetsoi]

The dos sound files are all creative lab voc files that pygame could read

$moonstone/SAMPLES$ file BALAND 
BALAND: Creative Labs voice data - version 1.10

but ggez/rodio cannot. Seeing as the DOS sound is terrible http://leastsignificant.blogspot.com/2018/05/moonstone-hard-days-knight-amiga.html it's probably just better to implement amiga sound and ignore dos for now.

The amiga sound files are all *.a files, e.g knight.a

$ file knight.a 
knight.a: IFF data, 8SVX 8-bit sampled sound voice

`knight.a is actually all the knight sounds concatenated together. So the parser would have to read all the those files and separate them out before reading them individually.

We'd need to implement 8svx as a rodio source https://docs.rs/rodio/0.10.0/rodio/source/trait.Source.html