More reorganization of wave and spectrum caches, and performance...

Simplify the partial copying of wave and spectrum caches.  Use memcpy for speed.

Don't memcpy out of the caches into temporary buffers for TrackArtist,
just pass
pointers.

More vectors in the cache classes, fewer deletes.

Pulled big loop, and its body, out of the spectrogram routine into functions.

src/WaveClip.h

@@ -72,41 +72,13 @@ public:
    float *min, *max, *rms;
    int* bl;
 
-   WaveDisplay()
-      : width(0), where(0), min(0), max(0), rms(0), bl(0)
+   WaveDisplay(int w)
+      : width(w), where(0), min(0), max(0), rms(0), bl(0)
    {
    }
 
    ~WaveDisplay()
    {
-      Deallocate();
-   }
-
-   void Allocate(int w)
-   {
-      width = w;
-
-      // One more to hold the past-the-end sample count:
-      where = new sampleCount[1 + width];
-
-      min = new float[width];
-      max = new float[width];
-      rms = new float[width];
-      bl = new int[width];
-   }
-
-   void Deallocate()
-   {
-      delete[] where;
-      where = 0;
-      delete[] min;
-      min = 0;
-      delete[] max;
-      max = 0;
-      delete[] rms;
-      rms = 0;
-      delete[] bl;
-      bl = 0;
    }
 };
 
@@ -193,13 +165,8 @@ public:
     * calculations and Contrast */
    bool GetWaveDisplay(WaveDisplay &display,
                        double t0, double pixelsPerSecond, bool &isLoadingOD);
-   void ComputeSpectrogramGainFactors(
-         int fftLen,
-         int frequencyGain, // db/decade
-         std::vector<float> &gainFactors
-      );
    bool GetSpectrogram(WaveTrackCache &cache,
-                       float *buffer, sampleCount *where,
+                       const float *& spectrogram, const sampleCount *& where,
                        int numPixels,
                        double t0, double pixelsPerSecond,
                        bool autocorrelation);