Autoquit improvement: On effect plugins where it's possible for the FX to silence the output, measure the levels of the input signal for autoquit

This so that the effect won't be turned off when there's input that the effect is muting (eg. when you use the Amplifier to temporarily mute a signal)

plugins/dynamics_processor/dynamics_processor.cpp

@@ -214,11 +214,10 @@ bool dynProcEffect::processAudioBuffer( sampleFrame * _buf,
 		s[0] *= outputGain;
 		s[1] *= outputGain;
 
+		out_sum += _buf[f][0]*_buf[f][0] + _buf[f][1]*_buf[f][1];
 // mix wet/dry signals
 		_buf[f][0] = d * _buf[f][0] + w * s[0];
 		_buf[f][1] = d * _buf[f][1] + w * s[1];
-
-		out_sum += _buf[f][0]*_buf[f][0] + _buf[f][1]*_buf[f][1];
 	}
 
 	checkGate( out_sum / _frames );