Release 21

changes:
- fix ADSR fractions (Resident Evil 3)
- fix reverb volume $3fff -> $7fff (Resident Evil 2)
- new output spu blocker (all games, buffer quality + improved latency)
- fix XA / CDDA distortion (all games)
- fix XA / CDDA interpolation (all games)
- fix XA / CDDA timing
- fix 1.00 Gaussian strengths
- fix SPU timing (Actua Soccer 2 + FIFA dropouts)
- fix A/V sync (Novastorm)
- fix mono + frequency response to work correctly
- $1000 jumps for dead channels creates halt (Metal Gear Solid)
- SPUsetframelimit to bypass spu blocker (shark only)


Presets are now stored in archive