Code/build cleanups.
diff --git a/MANIFEST.in b/MANIFEST.in
index b16d610..de1c916 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -2,6 +2,7 @@
 include LICENSE
 include MANIFEST.in
 include README.rst
+include tox.ini
 
 recursive-include docs *
 prune docs/_build