JOSS - rework setup.py

[glemaitre]

The setup.py is not really nice. I would advice to use a template as here

[glemaitre]

You should restrict the install to python 3 only since this is not python 2 compatible:
https://packaging.python.org/tutorials/distributing-packages/#python-requires

[glemaitre]

Improve the setup as well such that there information in the PyPi webpage.

[lfasnacht]

I improved setup.py. I didn't follow the logic in the shablona project, as I'm not fond of it. I used some inspiration from the pypa sample setup.py.

Is this file "nice enough"? Or do you see additional improvements?

[glemaitre]

It seems almost good. Could you take care about the PEP8.
Also it has to be check, for the long description I don't remember if you can give markdown or it needs to be rst to render properly on PyPi. But this point does not need to be addressed, you will see at the release time.

[lfasnacht]

It should work.

PEP8 is in my to-do list, but I'll do the code styling all at once, I'm working on the coverage at present.