improve debugging output
reduce our need to run external commands by shaving dd out of the equation
calculate sizes of partitions beforehand and ensure last (ZFS) partition ends 16 MB or so before the end of the disk.  This fixes ZFS zpool import trying to import the last partition as if it was a full disk.
bootpart UUID was wrongly gaining a newline. fix.
power off instead of reboot the VM
interactive qemu mode added as an option