A script for cloning a non-relocatable virtualenv.

Virtualenv provides a way to make virtualenv's relocatable which could then
be copied as we wanted. However making a virtualenv relocatable this way
breaks the no-site-packages isolation of the virtualenv as well as other
aspects that come with relative paths and '/usr/bin/env' shebangs that may
be undesirable.

Also, the .pth and .egg-link rewriting doesn't seem to work as intended.
This attempts to overcome these issues and provide a way to easily clone an
existing virtualenv.