Support installation via Pipsi

[techdragon]

Trying to install and use envie via the Pipsi tool, doesnt work. It seems to get confused about the paths and might just need to have some small modifications made so that when envie is living inside its own virtualenv it can still function.

[randomir]

I never tried installing Envie with Pipsi, but in principle, Envie should work inside a virtualenv. I'll test it with Pipsi. Thanks for reporting this.