Merge pull request #340 from alex6679/master

async_spdif_input constructor arguments

async_input_spdif3.h

 public:
 	///@param attenuation target attenuation [dB] of the anti-aliasing filter. Only used if newFs<fs. The attenuation can't be reached if the needed filter length exceeds 2*MAX_FILTER_SAMPLES+1
 	///@param minHalfFilterLength If newFs >= fs, the filter length of the resampling filter is 2*minHalfFilterLength+1. If fs y newFs the filter is maybe longer to reach the desired attenuation
-	AsyncAudioInputSPDIF3(bool dither, bool noiseshaping,float attenuation, int32_t minHalfFilterLength);
+	AsyncAudioInputSPDIF3(bool dither=true, bool noiseshaping=true,float attenuation=100, int32_t minHalfFilterLength=20);
 	~AsyncAudioInputSPDIF3();
 	virtual void update(void);
 	void begin();