Paul Licameli's Spectral Editing Patch.

This relies on three new nyquist scripts to actually do the editing.  The peak-snapping code in FrequencyWindow has been extracted into a new class, SpectrumAnalyst, to provide peak-snapping in spectrogram too.

src/export/ExportCL.cpp

@@ -18,6 +18,7 @@
 #include <wx/combobox.h>
 #include <wx/log.h>
 #include <wx/process.h>
+#include <wx/sizer.h>
 #include <wx/textctrl.h>
 #include <FileDialog.h>
 #include "Export.h"