Some Telnet server enhancements:

- PETSCII sending support
- Option to customize shell prompt and banner
- Stop all running commands on shell close
- New 'exit' and 'quit' commands to close shell

apps/serial-shell/serial-shell.c

@@ -77,6 +77,11 @@ shell_prompt(char *str)
 	 str);
 }
 /*---------------------------------------------------------------------------*/
+void
+shell_exit(void)
+{
+}
+/*---------------------------------------------------------------------------*/
 PROCESS_THREAD(serial_shell_process, ev, data)
 {
   PROCESS_BEGIN();