nixpart: New upstream version 0.4.0.

Changes are:

 - Properly detect GPT disklabels and create proper BIOS boot partitions
   if necessary.
 - Return exit code 100 if reboot is required due to the kernel not
   picking up the new partition table.
 - Don't include BIOS boot partition in GRUB devices.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>