RELEASE_CHECKOUT

- change version in VERSION
- if needed, change pysam version for OSX in .travis_deploy.sh (this is a workaround for pysam)
- change python3/doc/history.rst
- python2 setup.py build && python setup.py build
  (this makes _version.py and SWIGs _HTSeq.c)
- git add ...
- git commit ...
- git push fabio

(wait for CI to complete)

If all well:
- git tag release_<semantic-version>_RC1
- git push fabio release_<semantic-version>_RC1 (this repo has testpypi deploy triggers)
else:
- make changes on the branch and repeat (no additional version bump is needed)

(wait for CI to complete)

If all well:
- restart and, if necessary, update the pypi_CI branch
else:
- a minor version bump might be needed (pypi hates files with existing names)

If all well:
- git tag release_<semantic-version>
- git push fabio release_<semantic-version> (pypi deploy trigger)
- git push htseq release_<semantic-version> (github release deploy trigger)
- restart the CI build on the CI_pypi branch
- activate, triggen, and change default documentation page on readthedocs to the new release
- document release notes on github releases