* Error occurring with Pytest 5.4 so pin to below that version.
* Fix minor issues with Travis config.
* Use full command-switches for pytest in tox config.
* Remove pin for pip as issue with pip-wheel-metadata was fixed in 19.3
* Remove tox-venv as causing issues of incompatible packages installed.
The latest versions of the virtualenv package should handle these
duties.
There were issues with dependencies and tox environments under Python 3
so refactored the tox configuration to be more consistent and clearer.
- Moved travis to default to Python 3 for linting and tests.
- Fixed missing mock for cairo in sphinx config.
- Collated the base deps sections to improve readability.
- Added PYTEST_ADDOPTS env to override pytest verbosity in just tox
tests as this was a common option being used.
- Renamed env 'testcoverage' to the more concise 'coverage' and moved
html creation under single env as handy to have this output as well
as report.
- Cleaned up the isort config for gtk3.
- Added `bad-continuation` to pylint config as conflcts with black
formatting.
- Fix isort issue with bbfreeze script. This will likely be removed
in future so just skip sorting it.
- 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.
