Enable user to configure autodiscovery

.. select which kind of intervals we want

.. makes it faster and also reduces the size of
   the rideDB.json file quite dramatically which
   may be useful for some users.

src/RideSummaryWindow.cpp

@@ -361,6 +361,7 @@ RideSummaryWindow::refresh()
     }
 }
 
+#if 0 // not used at present
 static QString rankingString(int number)
 {
     QString ext=""; 
@@ -388,6 +389,7 @@ static QString rankingString(int number)
     }
     return QString("%1%2").arg(number).arg(ext);
 }
+#endif
 
 QString
 RideSummaryWindow::htmlSummary()