Debian packaging using dh-virtualenv

End result is this…

```
# dpkg -s nodeenv
Package: nodeenv
Status: install ok installed
Priority: extra
Section: contrib/python
Installed-Size: 7230
Maintainer: Eugene Kalinin <e.v.kalinin@gmail.com>
Architecture: amd64
Version: 0.9.4~dev-2014-06-17
Description: Node.js virtual environment builder
    .
    Tool to create isolated node.js environments, with its own
    installation directories, that doesn't share libraries with
    other node.js virtual environments.
    .
    These environments can be integrated with ones created by
    Python's virtualenv.
Homepage: https://github.com/ekalinin/nodeenv
```