This is interesting though in that, at least for me in Python 3.6
run via tox locally, it doesnt actually fail as would be expected
based on the report, and my own re-creation manually with a test
file... More investigation is needed.

Fix space in flag name

Previously, the line break in the source would result in
`--hang- closing` (note the space) being rendered in the HTML.

Fix missed quoting in E722 check

The warning looks fairly odd:

E722 do not use bare except'

change this to

E722 do not use bare 'except'

Document all supported Python versions as trove classifiers

Enable pip cache in Travis CI

Can speed up builds and reduce load on PyPI servers.

For more information, see:

https://docs.travis-ci.com/user/caching/#pip-cache

Include license file in the generated wheel package

Use MANIFEST.in to include LICENSE in the source distribution.

The wheel package format supports including the license file. This is
done using the [metadata] section in the setup.cfg file. For additional
information on this feature, see:

https://wheel.readthedocs.io/en/stable/index.html#including-the-license-in-the-generated-wheel-file

Add examples

Add W605 warning for invalid escape sequences in string literals

Starting with Python 3.6, invalid escape sequences in string literals
are now deprecated. In a future version of Python, invalid escape
sequences will be a syntax error. While this deprecation produces a
runtime warning, it only appears if warnings are enabled and the first
time the Python source is compiled to byte code. By adding a check to
pycodestyle, projects can take advantage of static analysis to catch and
fix these future syntax errors.

For more information on the deprecation, see the Python release notes,
https://docs.python.org/3/whatsnew/3.6.html#deprecated-python-behavior

> A backslash-character pair that is not a valid escape sequence now
> generates a DeprecationWarning. Although this will eventually become a
> SyntaxError, that will not be for several Python releases.

Fixes #633

Fix variable annotations

Had to catch a "No signature found for builtin <built-in method
search of _sre.SRE_Pattern object at 0x...>" in 3.4:

In python3.4 the search was not detected as a function, now that it's
wrapped in an lru_cache it is, yet it still has no signature (it has
in 3.5+).

See:

https://bitbucket.org/pypa/wheel/src/54ddbcc9cec25e1f4d111a142b8bfaa163130a61/wheel/bdist_wheel.py?fileviewer=file-view-default#bdist_wheel.py-119:125

http://pythonwheels.com/

I frequently use PyPI trove classifiers to check if a 3rd party package
is usable by my projects. Documenting the supported versions makes this
much easier for potential library users.

Users' global .gitattributes files may attempt to auto-fix certain files.

Python 3.6 invalid escape sequence deprecation fix

Use bisect instead of iterating over every offsets.

As the offsets looks already sorted (which looks logical so I assumed
they always are), using a bisection if faster than iterating over all
of them.

On a specific test I encontered, I got nice enhancement with this patch:

$ time python3 ./pycodestyle.py ~/Downloads/PmagPy/PmagPy/coefficients-552K.py > /dev/null

real 1m16.405s

$ time python3 ./pycodestyle.py ~/Downloads/PmagPy/PmagPy/coefficients-552K.py > /dev/null

real 0m3.318s

Avoid relying on inspect to list functions.

This allow to run python3 -m cProfile ./pycodestyle.py …. Otherwise,
as cProfile looks to wrap every functions (in a way I did not studied
in depth), the inspection of test function found no function, and no
test were run while running under cProfile, meaning that:

$ time python3 ./pycodestyle.py coefficients-148K.py
[loads and loads of errors properly reported]
real 0m4.712s
user 0m4.684s
sys  0m0.024s

$ time python3 -m cProfile ./pycodestyle.py /home/mdk/Downloads/pystyle/stats/git-clones/PmagPy/PmagPy/coefficients-148K.py
[no error reported as no check were found by inspection]
real   0m0.447s
user   0m0.436s
sys    0m0.008s

With this patch:

$ time python3 -m cProfile ./pycodestyle.py /home/mdk/Downloads/pystyle/stats/git-clones/PmagPy/PmagPy/coefficients-148K.py
[loads and loads of errors properly reported]
real 0m4.889s
user 0m4.852s
sys  0m0.032s

Correctly report E501 when the first line of a docstring is too long

Support case when the variable name start by a keyword, eg:
```
class Test:
    formula: str = None
```

Resolves #622

https://docs.python.org/3/whatsnew/3.6.html#deprecated-python-behavior

"backslash-character pair that is not a valid escape sequence now
generates a DeprecationWarning. Although this will eventually become a
SyntaxError, that will not be for several Python releases."

Spelling fixes

Add release notes for 2.3.1 as well

Add regression test for nested definitions

The bug was already fixed since it also affected E302 but this adds a
test to ensure it doesn't regress for nested definitions either.

Closes gh-619