* grub: update to latest release
* gnulib: update to match grub bootstrap.conf
* grub: build 32 and 64 bit EFI images
* syslinux: do not copy EFI image
* installer: adapt script to above changes
* mkimage: virtual: build only for 64-bit Generic
* mkimage: grub: create cfg / copy EFI images only for 64-bit Generic