add tox and flake 8 in install

pip3 install -U to avoid permission right

Revert python3.5 to python3, because python3.5 is not installed

Replace python3 with 3.5

Require ipython

Add stages 

Change running script

A console script has been added, blendunittest,  to run unittest under blender.
The blender unittesting file should start by blendtest, and be formatted according to unittesting convention.

The doc is now containing an item test, which will contains a list of all test written so far