- enhanced isohybrid call to know about --uefi option.
  Creating an EFI capable hybrid iso requires the new isohybrid
  tool including patches by Steffen Winterfeldt as well as
  a correctly prepared ISO to write the information. This commit
  is only about calling isohybrid whereas the last commits was
  about preparation of the iso itself
- fixed grub2 prefix and root variable setup (bnc #799488)
- fixed layout of iso's and also make sure fixCatalog()
  is called