The apidoc modules were not being generated on ReadTheDocs because
there is no way to run sphinx-apidoc manually.
Moved the running of sphinx-apidoc into conf.py.
Added zope.interface minimum version to fix Readthedocs warning.
- Add new requirements files to make it easier to install deps.
- Tox changes
- Update tox to use new requirements files.
- Tweak heading styles.
- Add development environment command `devenv`.
- Remove testenv command as it would run on devenv creation.
- Travis changes
- Now uses xenial as trusty is very old now.
- Trial run disabled to speed up tests.
- Add tox-venv for Python 3 support.
- Only install testssl if running security tests.
- Appveyor
- Add tox-venv for Python 3 support.
- Use requirements file for non-tox.
- Remove trial run to speed up testing.