added temporary fix to srtm download breaking because of no data fill…

…ing for bigger domain sizes, by increasing the nSearchPixels/dfMaxSearchDist from the default value of 100 to a value of 120 in gdal_util GDALFilBandNoData(). This at least makes it work for domains up to 30 km x 30 km in size, though something else is needed for even bigger domains. For issue #529

src/ninja/gdal_util.cpp

@@ -593,7 +593,7 @@ int GDALFillBandNoData(GDALDataset *poDS, int nBand, int nSearchPixels)
 
     poBand = poDS->GetRasterBand(1);
 
-    GDALFillNodata(poBand, NULL, 100, 0, 0, NULL, NULL, NULL);
+    GDALFillNodata(poBand, NULL, 120, 0, 0, NULL, NULL, NULL);
 
     double dfNoData = poBand->GetNoDataValue(NULL);