[Checkins] [zopefoundation/RestrictedPython] 1c4131: Rework tox ci config (#79)

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/zopefoundation/RestrictedPython
  Commit: 1c41318d0eb8cbe8664b90478ae80dfd4a2b3ab0
      https://github.com/zopefoundation/RestrictedPython/commit/1c41318d0eb8cbe8664b90478ae80dfd4a2b3ab0
  Author: Alexander Loechel <loechel at users.noreply.github.com>
  Date:   2017-09-18 (Mon, 18 Sep 2017)

  Changed paths:
    M .travis.yml
    A appveyor.yml
    A constraints.txt
    M src/RestrictedPython/_compat.py
    M src/RestrictedPython/compile.py
    M tox.ini

  Log Message:
  -----------
  Rework tox ci config (#79)

* move flake8 to a more generic lint / linter section and make that useable with Python 2 & 3

* introduce constraints.txt which for the start is empty, but could be used to pin / or exclude bad versions.

* add appveyor to test also on windows

* Allow Python 3.7 tests to fail, as this is still in development

* add optional autopep8 env to tox