Add RemoteCommand 'status' command.

As DMRGateway, it reports connection status.

Command sent: "status" to port: 7642
dstar:n/a dmr:conn ysf:n/a p25:n/a nxdn:n/a fm:n/a

RemoveCommand has been slighlty modified, as using Log on a read-only filesystem simply forbids the strings to be displayed.
Another solution would be to set LogInitialisse's filePath to "/tmp/" for *nix systems.

P25Network.cpp

@@ -424,6 +424,11 @@ unsigned int CP25Network::read(unsigned char* data, unsigned int length)
 	return c;
 }
 
+bool CP25Network::isConnected() const
+{
+	return (m_enabled && (m_addrLen != 0));
+}
+
 void CP25Network::close()
 {
 	m_socket.close();