Basic tox support

Signed-off-by: Michal Čihař <michal@cihar.com>
Add linkcheck to lint run

Signed-off-by: Michal Čihař <michal@cihar.com>
Consistently link to docs.weblate.org instead of mixing weblate.readthedocs.org and docs.weblate.org

Signed-off-by: Michal Čihař <michal@cihar.com>
Fix several external links

Signed-off-by: Michal Čihař <michal@cihar.com>
Consistenly link to Django 1.6 docs

Signed-off-by: Michal Čihař <michal@cihar.com>
Revert "Add linkcheck to lint run"

This reverts commit a4cc5b45a7f55d88dd3175b2ae8b3c9c41d9ccc8.

As urllib2 does not support SNI, this fails with many valid links.