Allow custom kernel command line
Build xorriso and vmdebootstrap args from cli options
Pass extra options to vmdebootstrap
Make cdroot a temporary location
Make cdhelp a temporary location
Validate anything downloaded by curl - check with debian-ftp or d-i how to validate
Logging everything
docstrings everywhere
More documentation
Unit tests
Try again if fetching the d-i helpers fails - don't just die, or at least say why you died
