Fatfs r015

[vchwe]

Hello Matt!

Following the discussion on SC forums, here are patches for hdfmonkey tool.

The first commit helps avoiding integer overflows by using the same (s)size_t type everywhere.

The second commit brings in the latest FatFs release 0.15. Since newer FatFat has removed a way to enforce specific FAT type (12, 16 or 32) during volume creation, the way --fat12/--fat16/--fat32 argument works for "create" command has changed slightly. Otherwise all operations should work the same way.

Thank you.