Check links in the documentation with tox
Fix Pocoo documentation links
Link to https version of python docs

To which the http version permanently redirects
Fix Jinja link
Switch pypi links to https

To which the http version redirects permanently
Switch packages.python.org to pythonhosted.org
Use https instead of http for docs.python.org
Use https for devcenter.heroku.com
Use libevent.org
Switch diveintohtml5.org to diveintohtml5.info