------------------------------------------------------------------------------------------
* Build documentation via Sphinx. Closes 14.
* Move development and packaging documentation to Sphinx.
* Restrict ``pycountry`` to ``16.11.8`` release because of bad Czech Republic
subdivision definitions.
* Remove popularity badge: PyPI download counters are broken and no longer
displayed.
* Move coverage config to ``setup.cfg``.
* Add ``test`` and ``develop`` dependencies.
* Only show latest changes in the long description of the package instead of
the full changelog.
* Replace ``pep8`` package by ``pycodestyle``.
* Enforce ``pycodestyle`` checks in Travis CI jobs.
* Test production of packages in Travis CI jobs.
* Always check for package metadata in Travis CI jobs.
* Make wheels generated under Python 2 environnment available for Python 3 too.
* Add link to full changelog in package's long description.