Since livecd-tools doesn't support starting Xen in EFI mode, most of its
EFI support is rewritten here (overriden in LiveEFIImageCreator, based
on imgcreate.LiveImageCreator).
This all is still temporary solution, until Xen will have mutiboot2+EFI
support - then almost standard configuration could be used (almost the
same grub config as for legacy boot). So keep the changes here, and when
the proper solution would be implemented, pursue to having it upstream.
QubesOS/qubes-issues#794
This comes with some overhead, at least at the beginning, because all
private images are copied there at system startup (instead of first
use). This uses about 450MB of RAM.
Still better than non-sparse private.img (2GB...).
