New SDK:

- Fixed ADPCM looping as per Deunan. Sakura Taisen 4 is distortion-free now, but ST3 still has some (possibly due to other causes?)
- I tried to get ADPCM interpolation going. And failed smirk
- Fixed some Skies of Arcadia songs from crashing - they were setting an active slot playing 16-bit samples' control register so that PCMS = 2, and thus adbase was NULL. Not sure exactly what real h/w would do here since neither KEYONEX or KEYONB are set in the new CTRL value.
- Ideas welcome on whatever we're still missing, notably the filter.