Code review comment for lp:~bart-jukie/vmbuilder/fixes

I have some misc patches for the python-vm-builder package. If you want me to fix anything up, let me know.

Summary:
 * added --post-install-script to run a script right after the image is built, but before it's transfered to the disk image.
 * added --variant to handle building a minbase debootstrap image.
 * make sure rootsize, optsize and swapsize are integers.
 * make it possible to install w/o console-steup.
 * fix some build issues.