* flake8 updates and cleanups
* Update to flake8 3.7.9.
* Update to flake8-bugbear 20.1.4.
* Only ignore errors in stub files.
* Remove obsolete error counts.
* Sort error codes alphabetically.
* Don't ignore the following errors (unneeded):
* E704 Multiple statements on one line (def)
* W504 Line break occurred after a binary operator
* B303 __metaclass__ used
* Remove obsolete comment
* Ignore F822 undefined name in __all__
This was introduced in a recent version (so it doesn't affect us right now but will if we upgrade the flake8 version used in tests). It gives errors like:
```
/home/travis/build/ambv/flake8-pyi/.tox/typeshed/tmp/typeshed/stdlib/3/re.pyi:21:9: E741 ambiguous variable name 'I'
/home/travis/build/ambv/flake8-pyi/.tox/typeshed/tmp/typeshed/stdlib/3/re.pyi:39:5: E741 ambiguous variable name 'I'
/home/travis/build/ambv/flake8-pyi/.tox/typeshed/tmp/typeshed/stdlib/3/re.pyi:58:5: E741 ambiguous variable name 'I'
/home/travis/build/ambv/flake8-pyi/.tox/typeshed/tmp/typeshed/third_party/2/OpenSSL/crypto.pyi:43:5: E741 ambiguous variable name 'O'
```
These aren't useful for typeshed, because regardless of whether it's good style, these libraries really do contain variables named `I` and `O`.
This commit disables following flake8 errors:
* F403: `‘from module import *’ used; unable to detect undefined names`
* F405: `name may be undefined, or defined from star imports: module`
We don't need to worry about undefined names since running mypy_test.py
should detect such undefined names.
- Removes references to 'runtests.sh', as it has been removed
- Adds links from the contributing file to the readme - testing section
- Updates flake8 stats
- Switch requirements-tests-py3.txt to use mypy GitHub master.
- Exclude .venv{2,3} (suggested in README.md) in .flake8 and .gitignore.
- Update instructions in README.md to be working.
- Remove runtests.sh script and mentions of it -- I can't get it to work
and the three steps are easily run by hand.
This simplifies running flake8 tests and reduces the amount of F821 errors
reported (flake8-pyi enables support for forward references in *.pyi files).
The error code is left disabled until I clean up the remaining issues.
This is currently disabled due to the high number of errors that need fixing.
I'll be committing fixes for them and updating the numbers in .flake8 until we
can enable linting for all files by default.
