Added a test that shows using virtual topics in a network of brokers to resolve some of the pain that comes up with durable subscriptions across a network. This test demonstrates the use of Virtual Topics and ConditionalNetworkBridgeFilterFactory with replayWhenNoConsumers=true
activemq/trunk/activemq-unit-tests/src/test/java/org/apache/activemq/usecases/VirtualTopicNetworkClusterReactivationTest.java