prevent npe with aggregation context results

src/main/java/fucoin/wallet/WalletImpl.java

@@ -30,7 +30,8 @@ public class WalletImpl extends AbstractWallet {
     private transient WalletGuiControl gui;
     private String preKnownNeighbourName;
     private boolean isActive;
-	private AggregationContext aggregationContext = new AggregationContextBuilder(null, null, null, null, null).build();
+	private AggregationContext aggregationContext = new AggregationContextBuilder(null, null, null, new double[] { -1 },
+			x -> x[0]).build();
 	private boolean hasPendingAggregationRequest = false;
     private ConcurrentLinkedQueue<ActorRef> deferedSupervisorReceivers = new ConcurrentLinkedQueue<>();
 	private transient final EvictingQueue<UUID> handledAggregationRequests = EvictingQueue.create(10);