plot parallel requests with style filledcurve

this makes the duration of requests more obvious

pdb-plotting/src/main/java/org/lucares/pdb/plot/api/ParallelRequestsAggregate.java

@@ -19,7 +19,7 @@ public class ParallelRequestsAggregate implements AggregateHandler {
 		for (final DataSeries dataSerie : dataSeries) {
 			final AggregatedData aggregatedData = dataSerie.getAggregatedData();
 			if (aggregatedData != null) {
-				appendfln(result, "'%s' using 1:2 notitle with lines axes x1y2 lw 1 %s, \\", //
+				appendfln(result, "'%s' using 1:2 notitle with filledcurve axes x1y2 lw 1 %s, \\", //
 						aggregatedData.getDataFile().getAbsolutePath(), //
 						dataSerie.getStyle()//
 				);