Fix using feedparser (old _getCharacterEncoding is gone).

Also, don't pretend to use .editorconfig when we don't use it (and
html2text doesn’t comply with it).

Also, finally PEP8ize whole script (otherwise it is difficult to use
flake8 on the code).

NOT YET FINISHED.

python3 html2text.py 'http://salonkritik.net/'

STILL FAILS

Fixes #18