.pep8: modified to work with flake8
.pep8 => .flake8 renamed
style/api: unused imports for "public" usage marked with "# noqa"
style: blank lines in the end of files removed
style: "E12x continuation line indentation" ignored
style: E221 & E203 fixes across files

E221 - multiple spaces before operator
E203 - whitespace before ':'
style: blank lines in the end of tests files removed
style: too long line split

E501 - line too long
style: missing blank line added

E301 - expected 1 blank line, found 0
style: django_settings/__init__ api "star" import ignored
flake8 check run added as a part of build process