audio: change output rate to 47340Hz, add resampler with small margin to elimiate pops/clicks due to output rate fluctuation

output rate is picked such that 1024 samples at that rate equal exactly 710 samples at the SPU's output rate

src/SPU.h

@@ -31,7 +31,7 @@ void SetBias(u16 bias);
 
 void Mix(u32 samples);
 
-void ReadOutput(s16* data, int samples);
+int ReadOutput(s16* data, int samples);
 
 u8 Read8(u32 addr);
 u16 Read16(u32 addr);