+ Pull in grub-efi for amd64 and i386
+ Lots of extra code in boot-x86:
- pull grub EFI pieces out of the latest debian-cd_info.tar.gz
blobs in d-i, if they're there. If so, use them to make x86 images
bootable via EFI (both via CD and USB)
- generate boot entries for grub on the fly; temporary code for now,
will switch to parsing the isolinux entries shortly instead.
- depending more and more on xorriso rather than genisoimage...