v5.1.15: Introduce wheel package

Bump version in preparation to create a new release

v5.1.14: Run tests in travis using tox

add binary wheel to source distribution

v5.1.13: Bump version

To make it match with the current tag and enable deployment, hopefully.

v5.1.12: Update .travis.yml

Updating encrypted PyPI password.

v5.1.11: Update .travis.yml

Quoting PyPI token var.

v5.1.10: Update .travis.yml

Replacing encrypted password with API token stored as an environment variable.

v5.1.9: Merge pull request #65 from Bengt/patch-1

Use python 3.6 for deployment stage

v5.1.8: Merge pull request #64 from Bengt/patch-1

Test more recent Python versions on Travis CI

Minor fixes to CPF and CI/CD.

Upgraded CI/CD pipeline to Python 3.5.

v5.1.6: Merge pull request #58 from rwl/runpf-bi-astype-int

Minor changes.