Release process:
- Make sure you are on the proper release branch
- Update the version in setup.py
- Update the version in doc/conf.py
- Update the version in .appveyor.yml
- Commit the changes with message "Changes for release X.Y.Z"
  git commit -m "Changes for release X.Y.Z"
- Make a git tag
  git tag vX.Y.Z
- Push to master the commit and the tag
  git push --tags central master
- Add a release on github with a tag in the form of 'vX.Y.Z'
  https://github.com/Theano/libgpuarray/releases/new
 - Make note of the major changes since the last release
