convertz - simple vm to live image conversion for zoni

Version 1.0:
Initial version, some self check for dependent tools/files, supports only Ubuntu
images with standard non-LVM 2 partitions (root and swap).

To Dos:
- possible bug in treating raw (.img) image as we work on the original image
  and not a copy of it thus lossing the original state after injecting live-*
  packages
- make self check independent or to run it during the installation/make process,
  possible even make necessary changes to the /etc/default/grub if necessary
- make use of nbd/qemu-nbd to skip conversion but possibly need to consider
  preserving the original image (in case user want it back)
- sync some of the variables in the script with those in the ZoniDefaults.cfg,
  will require some additional codes to be added to zoni
- probably need to port this to python