Refactor the Modem class hierarchy.

NullModem.cpp

@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2011-2018 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2011-2018,2020 by Jonathan Naylor G4KLX
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -19,9 +19,7 @@
 #include "NullModem.h"
 #include "Log.h"
 
-CNullModem::CNullModem(const std::string& port, bool duplex, bool rxInvert, bool txInvert, bool pttInvert, unsigned int txDelay, unsigned int dmrDelay, bool trace, bool debug) :
-CModem(port, duplex,rxInvert, txInvert,pttInvert,txDelay, dmrDelay, trace, debug),
-m_hwType(HWT_MMDVM)
+CNullModem::CNullModem()
 {
 }
 
@@ -29,7 +27,9 @@ CNullModem::~CNullModem()
 {
 }
 
-bool CNullModem::open(){
+bool CNullModem::open()
+{
 	::LogMessage("Opening the MMDVM Null Modem");
+
 	return true;
-}
+}