Update docs/changelog.txt

Update version in docs/conf.py, setup.py.

commit changes.

Tag a version, e.g.

git tag v1.0.0

push changes:

git push git push --tags

Upload release to pypi.python.org

python setup.py sdist bdist_wheel twine upload dist/*

Create a new release on https://github.com/python-cas/python-cas/releases