Setuptools pep8 command

Originally based on https://github.com/johnnoone/setuptools-pylint

This package exposes the pep8 style guide checker as a sub-command of setup.py:

$ cat setup.py
...
    setup(
        name='your project',
        setup_requires=['setuptools-pep8']
    )
....
$ cat setup.cfg
...
[pep8]
ignore=E225
...
$ python setup.py pep8
running pep8
./setup.py:41:1: W391 blank line at end of file

This invokes pep8 and applies any configuration from your setup.cfg file's [pep8] section. Typical use cases include simplification of continuous-integration job configurations.