Initial commit for em4x70 support.

Initially I only have an em4x70 variant used for car transponders.
Also known as the ID48.

client/src/cmdlfem4x70.h

@@ -0,0 +1,25 @@
+//-----------------------------------------------------------------------------
+// Copyright (C) 2020 sirloins
+//
+// This code is licensed to you under the terms of the GNU GPL, version 2 or,
+// at your option, any later version. See the LICENSE.txt file for the text of
+// the license.
+//-----------------------------------------------------------------------------
+// Low frequency EM4x70 commands
+//-----------------------------------------------------------------------------
+
+#ifndef CMDLFEM4X70_H__
+#define CMDLFEM4X70_H__
+
+#include "common.h"
+#include "em4x50.h"
+
+#define TIMEOUT                     2000
+
+int CmdLFEM4X70(const char *Cmd);
+int CmdEM4x70Info(const char *Cmd);
+
+int em4x70_info(void);
+bool detect_4x70_block(void);
+
+#endif