Prevent duplicate analyzer registrations

src/de/tud/kom/p2psim/impl/common/DefaultMonitor.java

@@ -85,7 +85,9 @@ public class DefaultMonitor implements MonitorComponent, EventHandler,
 
 	@Override
 	public <A extends Analyzer> void registerAnalyzer(A analyzer) {
-		analyzers.add(analyzer);
+		if (!analyzers.contains(analyzer)) {
+			analyzers.add(analyzer);
+		}
 	}
 
 	@Override