Add custom RTMP port number support (#462)

* Bump api spec version

* Add support for custom RTMP port. Closes #454

core/rtmp/rtmp.go

@@ -30,12 +30,12 @@ var _rtmpConnection net.Conn
 var _setStreamAsConnected func()
 var _setBroadcaster func(models.Broadcaster)
 
-// Start starts the rtmp service, listening on port 1935.
+// Start starts the rtmp service, listening on specified RTMP port.
 func Start(setStreamAsConnected func(), setBroadcaster func(models.Broadcaster)) {
 	_setStreamAsConnected = setStreamAsConnected
 	_setBroadcaster = setBroadcaster
 
-	port := 1935
+	port := config.Config.GetRTMPServerPort()
 	s := rtmp.NewServer()
 	var lis net.Listener
 	var err error