Update Buildbot URL.
Update tox URL.
Update Travis CI URL because always https.
Use Wayback Machine to resolve a dead link.
Add Qt link.
Update Gunicorn help link.
Update link to Gondor documentation.
Update virtualenvwrapper documentation links.
Update link to 'A Byte of Python'.
Add link to 'Python in a Nutshell'.
Update Buildbot URL.
Update tox URL.
Update Travis CI URL because always https.
Use Wayback Machine to resolve a dead link.
Add Qt link.
Update Gunicorn help link.
Update link to Gondor documentation.
Update virtualenvwrapper documentation links.
Update link to 'A Byte of Python'.
Add link to 'Python in a Nutshell'.