Support for the old-style attributes was dropped in django-extra-views 0.11.

Also pin the version as the package does not use semantic versioning.

Fixes #2688.

We cannot rely on this being installed by django-phonenumber-field.
See https://github.com/django-oscar/django-oscar/issues/2681.

Fixes #2681.

Just released, that’s why

v2.0.0a was released recently which we are not yet compatible with.

The blocking dependency (Haystack) now supports Django 2.

Just assume django-haystack uses semver for now.

pytest-warnings is now part of pytest core. See https://docs.pytest.org/en/latest/changelog.html#id71

- Drop support for Django 1.9 (EOL)
- Drop support for Python 3.6 with Django 1.8 to 1.10

travis: Run py.test --cov=oscar instead of coverage run

This also updates the pytest dependencies

As per [their blog post of the 27th April](https://blog.readthedocs.com/securing-subdomains/) ‘Securing subdomains’:

> Starting today, Read the Docs will start hosting projects from subdomains on the domain readthedocs.io, instead of on readthedocs.org. This change addresses some security concerns around site cookies while hosting user generated data on the same domain as our dashboard.

Test Plan: Manually visited all the links I’ve modified.

Recent babel releases contain several bugfixes.

We only support two versions of Django. That policy might change given
that Django has started doing LTS releases. But for now, it only makes
sense to remove Django 1.7 support.