[tox] Do not install package in "develop"
This might shadow so packaging issues.
And user can still pass --develop to tox.
.. -*- coding: utf-8 -*-
Server Architecture
-------------------
.. image:: images/server-class-diagram.png
`Diagramme ArgoUML`_
[FIXME]
Make a downloadable source of zargo file.
.. _`Diagramme ArgoUML`: cubicweb.zargo