Use setuptools to bundle the application

[AntoineGagne]

As the title says, this change the project structure so that it is installable with setuptools.

Also, the application uses argparse for parsing the command line arguments now.

I also added support for Sphinx documentation.

Finally, I added tox support for running pytest, pylint and flake8 (although I have not fixed the warnings). This might be useful in case you want to setup TravisCI.