UDPListener improvements: (#53)

- if you listen to a multicast address, it now also listens to all ipv4 addresses
- shared udp sockets - multiple hyperiond instance can optionally share the same udp packets

src/hyperiond/hyperiond.cpp

@@ -251,7 +251,8 @@ void HyperionDaemon::startNetworkServices()
 						udpListenerConfig.get("priority",700).asInt(),
 						udpListenerConfig.get("timeout",10000).asInt(),
 						udpListenerConfig.get("address", "").asString(),
-						udpListenerConfig.get("port", 2801).asUInt()
+						udpListenerConfig.get("port", 2801).asUInt(),
+						udpListenerConfig.get("shared", false).asBool()
 					);
 			Info(_log, "UDP listener created and started on port %d", _udpListener->getPort());
 		}