Sysadmin documentation: reorganize install instructions

[ael-code]

we should provide different instructions for:

• install libreant ( bdist_egg ) :

  I guess using easy_install do not require all the dependencies listed now in the README

• install libreant from sources ( sdist ) :

  maybe we could skip this one.

• create a development environment:

  Step by step how to create a development env

[boyska]

Mh, what do you mean exactly? I see some scenarios:

• developer; wants to develop with the latest version, so it'll need to setup a virtualenv, and do python setup.py develop
• sysadmin; wants to install the latest stable version; that is, the one that is on PyPI. It just need to run pip install libreant or easy_install libreant (according to his tastes)
• sysadmin with bleeding edge; wants to try a new version, so download the latest version and run python setup.py install

I think that the sdist/bdist_egg thing is mostly for developers when they need to do a release. More than installing, those commands are about packaging.

Anyway, we'll surely benefit making these scenarios cleaner.

[boyska]

The developer part is covered by #84, so you should only care about sysadmins. I don't know if we are interested in explaining how to install the latest version from git. If we are ( @leonaard, you decide!), I discovered that

pip install git+https://github.com/insomnia-lab/libreant.git 

does what you think.

[boyska]

Maybe @g3-3k want to do this, also?