Added --convert-fstab-to-partuuid option that converts a device name
using fstab and cmdline.txt to use PARTUUID as is standard in recent
Raspbian distributions. Just a helper option for users that want to
convert.
Added back in clone to smaller 4GB card example.
Implemented Peter Collinson's idea for preserving the SD card cmdline.txt
that is set up to boot to USB when cloning from USB back to the SD card.
Update README.md examples.
Previously SD card mmcblk0 was hardwired as the source disk so clones from
USB disk did not work. Using mtab to get the booted disk allows cloning
from USB disks. Should that fail, a -s option can force the source disk.
The source disk must be the booted disk.
Cross Filesystem Feature
Split rsync into 2 separate processes, 1 for /boot, 1 for rest of filesystem
and add -x rsync flag to make not crossing filesytem boundaries the default.
Added --cross-filesystems switch to reproduce old behaviour.
If using dphys swapfile, exclude it from the rsync clone.
Jessie versions of parted and fdisk have some changes to account for:
* Add a missing -s flag to one of the parted commands.
* Dump parted stderr to /dev/null since it now complains about destination
disk partitions ending outside of disk before I get chance to resize
the partitions.
* Strip trailing s from PART_START - (fdisk now doesn't seem to accept...)
