Add config options for ListenAddr & Interfaces

These options are helpful when the bridge is running on a multi-homed
device like a wireless router.

hapz2m.conf

@@ -1,4 +1,12 @@
 {
+	// specify a host:port to listen on
+	// if not specified, a random port will be used
+	//"ListenAddr": ":8585",
+
+	// limit interfaces to use for DNS-SD (mDNS)
+	// leave blank for all interfaces
+	//"Interfaces": ["eth0", "eth1"],
+
 	// MQTT server credentials
 	"Server": "tcp://localhost:1883",
 	"Username": "hapz2m",