MP3 decoder

[Ryan C. Gordon]

> This patch (developed using patent-pending trial-and-horror technology)
> seems to finally fix the MP3 decoder.

Aha!

Great...I've applied it to CVS, and flipped the use_decoder_mp3 flag in
the Makefile.

I'm also going to look at patch SMPEG so that mixing can be turned off on
an individual (SMPEG *) basis. Most situations don't need that, it's
confusing, and it's less efficient.

Now if mpg123's mpglib actually built as a shared library...  :)

--ryan.