Makefun

- Fixed `ValueError: Invalid co_name` happening on python 2 when the name of a function to create starts or ends with
`_` or contains a double `__` . Fixes [91](https://github.com/smarie/python-makefun/issues/91)

- `wraps` now always sets the `__wrapped__` attribute, and also sets the `__signature__` attribute when the signature changes, as specified by PEP 362. PR []() by [86](https://github.com/smarie/python-makefun/pull/86) by [lucaswiman](https://github.com/lucaswiman).

- `create_wrapper`, `create_function`, `wraps` and `with_signature` now support lambda functions. They also accept a new parameter `co_name` to define the name to be used in the compiled code. PR [80](https://github.com/smarie/python-makefun/pull/80) by [andrewcleveland](https://github.com/andrewcleveland).

1.13.1 - Fixed regression with generators in python 3.5

- Fixed an issue where using `partial` on a generator function in python 3.5 was raising a `SyntaxError`. Fixed [79](https://github.com/smarie/python-makefun/issues/79)

- async generator functions are now supported (See [PEP525](https://www.python.org/dev/peps/pep-0525/)). Fixed [#77](https://github.com/smarie/python-makefun/issues/77). [PR#78](https://github.com/smarie/python-makefun/pull/78) by [broglep-work](https://github.com/broglep-work).

- Fixed `TypeError` when a `func` attribute is present on the function provided to `create_function`. Fixed [76](https://github.com/smarie/python-makefun/issues/76)

- Fixed `partial` so that :
- when no argument is provided, it is equivalent to `wraps(f)(f)`. That is, the `__wrapped__` attribute is set. Fixed [73](https://github.com/smarie/python-makefun/issues/73)
- it sets the `func` attribute just as `functools.partial` does. Fixed [75](https://github.com/smarie/python-makefun/issues/75)
- Removed `pytest-cases` dependency as it was a circular one. Fixed [68](https://github.com/smarie/python-makefun/issues/68)
- Now using `flake8` for qualimetry and `genbadge` for badges. Fixed [71](https://github.com/smarie/python-makefun/issues/71)
- Restructured project so that tests are truly independent, to ease rpm/apt/etc. packaging. Fixed [69](https://github.com/smarie/python-makefun/issues/69)