setup.py - correct distiller version

Fix copy-paste mistake

setup.py

@@ -10,7 +10,7 @@ with open('requirements.txt','r') as req_file:
     install_reqs = [line.strip() for line in req_file.readlines()]
 
 setup(name='distiller',
-      version='0.3.0-pre',
+      version='0.4.0-pre',
       packages=packages,
       install_requires=install_reqs
       )