GWC release 0.21-10

Well, I had a lot of great plans for GWC, but also I had a busy life, so not much got done.

But, lack of releases does generally mean "it isn't broke", as far as I know. I read on some mailing list some person saying GWC was not worth looking at because there had been no recent development. I think that logic is seriously flawed.

But I do have a major bugfix here, and a minor one as well. ALSA playback could at times crash gwc. I tracked that down and fixed it. Also some of the code for the biquad filtering was poor, causing samples to be interchanged between the right and left channels. That's fixed too.

Enjoy!