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.

DMRGatewayNetwork.cpp

@@ -287,6 +287,11 @@ bool CDMRGatewayNetwork::writeTalkerAlias(unsigned int id, unsigned char type, c
 	return write(buffer, 15U);
 }
 
+bool CDMRGatewayNetwork::isConnected() const
+{
+	return (m_enabled && (m_addrLen != 0));
+}
+
 void CDMRGatewayNetwork::close()
 {
 	LogMessage("DMR, Closing DMR Network");