Use newer twisted.

adiroiban · adiroiban · commit 9c6204133f5b · 2015-03-24T10:07:42.000Z
diff --git a/setup.py b/setup.py
@@ -42,7 +42,7 @@
     ],
     extras_require = {
         'dev':  [
-            'twisted==13.2.0',
+            'twisted>=15.0.0',
             'pyflakes==0.8.1',
             ],
     },
