* Remove unneeded sys import.
Once upon a time we needed this in some of these setup.py files because we were
using sys in the file, but we aren't anymore so let's remove the import.
* use setuptools instead of distutils
* Drop support for EOL Python 2.6
* Use more helpful assertIn/NotIn instead of assertTrue/False
* Drop support for EOL Python 3.3
* Remove redundant Python 3.3 code
* Restore code for RHEL 6 and virtualenv for Py2.7
* Revert pipstrap.py to upstream
* Merge py26_packages and non_py26_packages into all_packages
* Revert changes to *-auto in root
* Update by calling letsencrypt-auto-source/build.py
* Revert permissions for pipstrap.py
* Use pipstrap to install a good version of pip
* Use pytest in cb-auto tests
* Remove nose usage in auto_test.py
* remove nose dev dep
* use pytest in test_tests
* Use pytest in tox
* Update dev dependency pinnings
* remove nose multiprocess lines
* Use pytest for coverage
* Use older py and pytest for old python versions
* Add test for Error.__str__
* pin pytest in oldest test
* Fix tests for DNS-DO plugin on py26
* Work around bug for Python 3.3
* Clarify dockerfile comments
* Pin oldest version of packaged python deps
* Install security extras in oldest tests
* Revert "bump requests requirement to >=2.10 (#4248)"
This reverts commit 402ad8b353.
* Use create=True when patching open on module
* Mention python 3 support in setup.py
* Build universal (py2 and py3 compatible) wheels
* Mention Python 3.3+ support in docs
* we work on python 3.6 too
* stop conditionally pinning mock version in acme
* stop conditionally pinning mock version in certbot
* stop conditionally pinning mock version in apache
* stop conditionally pinning mock version in nginx
* stop conditionally pinning mock version in letshelp
* stop conditionally pinning mock version in compatibility-test
