added client.begin() with callback

src/DidacticNet.cpp

@@ -184,6 +184,11 @@ void DidacticPSNetClient::begin(Stream &_port) // TODO: check if CLientMode is n
   _clientMode = CLIENT_MODE_BASIC;
 }
 
+void DidacticPSNetClient::begin(Stream &_port, PSNET_CALLBACK_SIGNATURE)
+{
+  DidacticPSNet::begin(_port, callback);
+}
+
 bool DidacticPSNetClient::available()
 {
   return _newMessageAvailable;

src/DidacticNet.h

@@ -193,6 +193,7 @@ public:
 	~DidacticPSNetClient();
 
 	void begin(Stream &_port); // new
+	void begin(Stream &_port, PSNET_CALLBACK_SIGNATURE);
 
 	bool available();				  // new
 	int readLatestTopicNr();		  // new