Updated mp3 downloads, ogg+flac now available

I've ported this over to pyBlamscamp, my automated end-to-end encoding and publishing pipeline, which was originally based on blamscamp but pretty much all that remains from that now is most of the preview player. Maybe I should have used a less-confusing name. But whatever.

Anyway, the end result of this is that the mp3 downloads are now higher-bitrate than the old Bandcamp-encoded version, and there's also ogg and FLAC versions as well. Also the web player is a little nicer in some ways.