add dump.exfat to extract exfat medata from device which is formatted by exfat.
add restore.exfat to make clone device using a dump image that made by dump.exfat.
add debug.exfat debug method to check exfat metadata informaton from a dump image to analyse corrupted exfat.
a. show boot sector, bitmap, and fat table info.
b. show file list and can select file and show file info(bitmap and fat table info, directory entry info)