* Avoid virtual method hiding warnings

* Avoid potential deadlock in thread join when processing has been abandoned

src/SpectralDifferenceAudioCurve.h

@@ -31,6 +31,7 @@ public:
     virtual void setWindowSize(size_t newSize);
 
     virtual float process(const float *R__ mag, size_t increment);
+    virtual float processDouble(const double *R__ mag, size_t increment);
     virtual void reset();
 
 protected: