Fix UserWarning: Normalizing '0.2.9dev' to '0.2.9.dev0'

xvfbwrapper/lib/python3.4/site-packages/setuptools/dist.py:285: UserWarning: Normalizing '0.2.9dev' to '0.2.9.dev0'

setup.py

@@ -24,7 +24,7 @@ except ImportError:
 
 setup(
     name='xvfbwrapper',
-    version='0.2.9dev',
+    version='0.2.9.dev0',
     py_modules=['xvfbwrapper'],
     author='Corey Goldberg',
     author_email='cgoldberg _at_ gmail.com',