USB Mass Storage Device demo with SD card

Dependencies:   USBDevice USBMSD_SD max32630fthr

Fork of FTHR_USBMSD_Demo by Greg Steiert

This pull request has been rejected by Maxim Integrated

Update for latest block device API

This updates the demo to utilize the latest block device API which allows for support of other block storage devices, including the heap block device.

This is a block device implementation of the USB MSD driver. It will allow you to easily change between different storage devices that implement the block device API.