Recommend additional header comments to UHS_FS_NEW_DEMO.ino

[WonkoSan]

Hello,

I would like to recommend adding additional header and introduction comments/documentation for the UHS_FS_NEW_DEMO.ino example.

Full path to file:
UHS30/libraries/UHS_FS/examples/USB_HOST_SHIELD/UHS_FS_NEW_DEMO/UHS_FS_NEW_DEMO.ino

I am currently adapting UHS30 to use a USB thumb drive as a flash storage device as a file system for my Project.

While reading the example code and trying to compile and deploy the example, it took me several days to fully understand the importance of defining the Volume Label correctly. Until the VOL_LABEL matched what the usb drive had, the demo would not work correctly.

I would like to recommend adding extra emphasis at the top of the header for this example to underscore and really highlight the essential importance of this configuration step. This is of particular value to new users who may not be as familiar with debugging code and just want to get up-and-running as quickly as possible. Here is my suggestion addition to the header comment:

// ******* IMPORTANT ******* READ THIS FIRST !
// You MUST define the VOL_LABEL correctly to match what is on your USB Device, or else
// the call to mount the USB mass storage volume will not succeed and this demo will fail to run
// properly and will fail to recognize the volume.
// On Windows, volume labels may be defined at the Command Line by the command label.
// On MacOS, volume labels may be changed using /usr/sbin/diskutil rename
// On Linux, volume lablels may be changed using mlabel or e2label

// define the label of your filesystem. VOL_PATH must end in '/'
// Example:
// #define VOL_LABEL "/foo"
// #define VOL_PATH "/foo/"

#define VOL_LABEL "/"
#define VOL_PATH "/"`

Also: suggest adding a possible solution to the Print Statement:

printf_P(PSTR("No media. Waiting to mount. Check VOL_LABEL is defined to match USB drive. " VOL_LABEL "\r\n"));

Thank you.

[xxxajk]

Do a pull request, this is a good idea. :-)