Pytest-cases

- Better support for `pytest.param` in `parametrize_plus` and also in `fixture_union` and `fixture_param[s]`. Improved corresponding ids. Fixed [79](https://github.com/smarie/python-pytest-cases/issues/79) and [#86](https://github.com/smarie/python-pytest-cases/issues/86)

- New `ignore_unused` decorator to protect a fixture function from the "NOT_USED" case happening when the fixture is used in a fixture union.

- Removed `six`, `wrapt` and `enum34` dependencies

- (Internal) submodules reorganization for readability
- (Internal) suppressed a lot of code quality warnings

See [documentation page](https://smarie.github.io/python-pytest-cases/changelog/) for details.

- Fixed `ids` precedence order when using `pytest.mark.parametrize` in a `fixture_plus`. Fixed [87](https://github.com/smarie/python-pytest-cases/issues/87)

- Fixed issue with `fixture_union` when using the same fixture twice in it. Fixes [85](https://github.com/smarie/python-pytest-cases/issues/85)

- Added the possibility to pass a `hook` function in all API where fixtures are created behind the scenes, so as to ease debugging and/or save fixtures (with `stored_fixture` from pytest harvest). Fixes [83](https://github.com/smarie/python-pytest-cases/issues/83)

- Fixture closures now support reordering when no unions are present. This suppressed the annoying warning "WARNING the new order is not taken into account !!" when it was not relevant. Fixes [81](https://github.com/smarie/python-pytest-cases/issues/81)

See [documentation page](https://smarie.github.io/python-pytest-cases/changelog/) for details.

- packaging improvements: set the "universal wheel" flag to 1, and cleaned up the `setup.py`. In particular removed dependency to `six` for setup and added `py.typed` file. Fixes [78](https://github.com/smarie/python-pytest-cases/issues/78)

See [documentation page](https://smarie.github.io/python-pytest-cases/changelog/) for details.

`cases_generator` now has a default value for the `names` template, based on the parameters. Fixes [77](https://github.com/smarie/python-pytest-cases/issues/77).

See [documentation page](https://smarie.github.io/python-pytest-cases/changelog/) for details.

Fixed `ValueError` when a product of unions was used on a test node, for example when two `parametrize_plus` using `fixture_ref`s were used on the same fixture or test function. Fixed [76](https://github.com/smarie/python-pytest-cases/issues/76)

See [documentation page](https://smarie.github.io/python-pytest-cases/changelog/) for details.

Improved error message when something that is not a fixture is used in `unpack_fixture` or `fixture_union`. Fixed [75](https://github.com/smarie/python-pytest-cases/issues/75)

See [documentation page](https://smarie.github.io/python-pytest-cases/changelog/) for details.