Fix namespace packaging.

Just oops.... I also updated tox.ini so that it checks all-the-things
and works again.

setup.cfg

@@ -29,6 +29,10 @@ classifiers =
 	Topic :: Software Development :: Libraries :: Python Modules
 
 [options]
+namespace_packages =
+	sprockets
+	sprockets.mixins
+packages = find:
 install_requires =
 	ietfparse>=1.5.1,<2
 	tornado>=5,<7

tox.ini

@@ -1,14 +1,27 @@
 [tox]
-envlist = py37,py38,py39
+envlist = py37,py38,py39,coverage,docs,lint
 indexserver =
-	default = https://pypi.python.org/simple
+    default = https://pypi.python.org/simple
 toxworkdir = build/tox
 skip_missing_interpreters = true
 
 [testenv]
-deps =
-    -e .[msgpack]
-    -r requires/testing.txt
+usedevelop = true
+extras =
+    dev
+    msgpack
 commands =
-    coverage run -m unittest []
-    coverage report
+    python -m unittest tests.py
+
+[testenv:coverage]
+commands =
+    coverage run -m unittest tests.py
+    coverage report 
+
+[testenv:docs]
+commands =
+    sphinx-build -b html -aEn docs {envtmpdir}/sphinx
+
+[testenv:lint]
+commands =
+    flake8 sprockets tests.py