- added Msg frame work with Msg container , Msg sources, Msg sinks

- added filter by message type to nmea receiver
- show case new features in MultiClient.main()

msg_sink.py

@@ -0,0 +1,10 @@
+from abc import ABC, abstractmethod
+from msg_montainer import MsgContainer
+
+class MsgSink(ABC):
+	def __init__(self):
+		pass
+
+	@abstractmethod
+	def on_recv(self, msg: MsgContainer):
+		pass