Add example RoutingMasterPolicy classes
artdaq-demo should contain examples of the RoutingMasterPolicy plugin type. Two have been added:
1. MisbehaviorTest_policy: This RoutingMasterPolicy is like ToyHardwareInterface in that it can be configured to "misbehave". In this case, it can be configured to send several different type of invalid Routing Table data, allowing the DataSenderManager to show its resilience against corrupt Routing Table data.
2. NthEvent_policy: This RoutingMasterPolicy acts as a round-robin except that every "nth" event is sent to a "special" receiver.
Corresponding tests for these policies have also been added.