Use of setup.cfg

It is a the now and future of module configuration. Replace content of setup.py with something more readable/parsable in setup.cfg.

We will also rename the package to nuxeo. It is more logical and easy for users to pip install nuxeo and then import nuxeo than using nuxeo-python-client.

So, for those whose who have nuxeo-python-client installed, they will not receive upgrades anymore. The "fix" is simple:

pip uninstall nuxeo-python-client
pip install nuxeo

This is why the version number will be 2.0.0.