Add facility to degrade S/N of data from .wav files.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6165 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

mainwindow.cpp

@@ -1531,6 +1531,9 @@ void MainWindow::diskDat()                                   //diskDat()
   int kstep=3456;
   m_diskData=true;
 
+  float db=m_config.degrade();
+  if(db > 0.0) degrade_snr_(jt9com_.d2,&jt9com_.kin,&db);
+
   for(int n=1; n<=m_hsymStop; n++) {                      // Do the waterfall spectra
     k=(n+1)*kstep;
     if(k > jt9com_.kin) break;