In Python 3, the default encoding of source files is utf-8. The encoding
cookie is now unnecessary and redundant so remove it. For more details,
see the docs:
https://docs.python.org/3/howto/unicode.html#the-string-type
> The default encoding for Python source code is UTF-8, so you can
> simply include a Unicode character in a string literal ...
Includes a fix for the flake8 header checks to stop expecting an
encoding cookie.
The meaning of `\w` changed from python 2 to python 3.
> $ python3.5 -c "import re; print(re.compile(r'[a-zA-Z]\w*$').match(u'a\xe8'));"
> <_sre.SRE_Match object; span=(0, 2), match='aè'>
> python -c "import re; print(re.compile(r'[a-zA-Z]\w*$').match(u'a\xe8'));"
> None
but the definition of what's an acceptable javascript identifier should not vary from case to case.
