Consolidate CI tools into setup.cfg and drop tox

src/tox.ini

@@ -1,22 +0,0 @@
-# Tox (http://tox.testrun.org/) is a tool for running tests
-# in multiple virtualenvs. This configuration file will run the
-# test suite on all supported python versions. To use it, "pip install tox"
-# and then run "tox" from this directory.
-
-[tox]
-skipsdist = True
-envlist = py34, py35, py36, pycodestyle
-
-[testenv]
-commands = pytest
-deps = -r{toxinidir}/../requirements.txt
-
-[testenv:pycodestyle]
-commands=pycodestyle
-deps=pycodestyle
-
-[pycodestyle]
-exclude=
-  .tox,
-  migrations,
-  paperless/settings.py