this makes it easier to upgrade to Python 3 since less on_delete lines
have to be fixed.

squash all migrations

Tests coverage

Tests cov

travisci runs tests on a different distro, so libalpm is not testable.

Adopt tests

urls: add no cover pragma for unused show_urls

Netboot test

news: Add tests for all news functionality

Js deprecated

The only user of format_filesize is visualize.js, move the code there to
reduce archewb.js which is loaded on multiple pages.

In 373a426c we removed the i686/x64_64 differences report and forgot to
remove the used JavaScript functions.

.attr() is deprecated in jQuery so use .prop() to switch the checkboxes.

Fix Foreignkey implicit on_delete on django < 2.0

Foreignkey used to implicitly be on_delete=models.CASCADE and has to be
explicit now.

Django deprecations

Use is_authenticated as an attribute.

MIDDLEWARE_CLASSES is deprecated in Django 1.10.