Remote management commands

These commands can be used to remotely configure VTAP reader settings, without the need to connect the VTAP reader over USB and use its mass storage.

Modify or add settings in config.txt using $<setting>=<value>.
Example: Send $PassBeep to set the buzzer response on successful pass read
Copy
```
$PassBeep=100,100,2
```
This will result in the VTAP response:

OK
Note: Any update to config.txt using a $<setting> command will cause the USB file system to be remounted. This is forcing the operating system to refresh its file system cache, and will appear as if the mass storage drive has been momentarily removed then reconnected.

CAUTION: Frequent changes in config.txt causes flash memory degradation. If your application requires frequent temporary configuration changes, use dynamic commands to avoid frequent updates to the config.txt file.
Use !<filename> to retrieve files saved on the VTAP reader to any connected system, over Zmodem. When this command is sent to the VTAP reader, it will start polling for the 'file transfer initiation acknowledgement' from your connected system, by sending a header. When TeraTerm, PuTTY, or your own custom software, acknowledges the first header, a Zmodem file transfer will begin and the file will be transferred. Use this command when you need to modify or add many settings in config.txt, or change patterns/animations in leds.ini. You could also use this setting to make a backup copy of the current config.txt or boot.txt.