When rendering an extension's static media files in debug mode, the

resulting HTML is returned as unsafe text. This can lead Django to

escape the contents, breaking pages and showing HTML source in the

pages.
This fixes this by explicitly marking the HTML as safe. The bulk of the

change, though, is to the unit tests. We now have two versions of most

of the tests: One with Pipeline enabled, one with Pipeline disabled.

This gives us full test coverage of this logic so that neither mode can

regress without tests failing in the future.

Unit tests pass on all supported versions of Django and Python.