Defaulting to a plaintext response makes no sense for an endpoint that is intended to be used by machines for testing. The endpoint now returns JSON only unless a redirect action is triggered.

This reverts commit f97f0525, reversing
changes made to 800bcd8e.

- Removed unused imports
- Ran isort to properly order/style imports

This makes it possible to refer to multiple book from a single app.

This also means that Open edX branches will be able to pass bok-choy
tests (at least if the books have already been built.)

* Updated the SASS to point to the Pattern Library
* Removed duplicate copies of fonts

TNL-5046

and moving progress page tests into separate file

TNL-1958

Stop clearing the entire mongo collection with every mixin instantiation.
Instead, reset the clock for the particular test.

With this approach, filters must be stricter, for example, according
to username or user id.

Bok-Choy test added for SOL-1196 to verify no black box around view certificate note in Progress Tab

TNL-3198

Also fixed a regression with the search breadcrumbs
where it wasn't possible to navigate back to the
full list.

The old line:

    from path import path

produced pylint errors because of the baroque way that path.py defined
"path".  We tried to get them to change how they defined it, but they
deleted the name instead: https://github.com/jaraco/path.py/issues/102

(Jason then changed his mind, but this is a better way to use path.py,
it avoids the pylint error at least.)

TNL-2413

TNL-2413

Sometimes this file does not exist depending on when a test failed. Remove it gracefully.

TNL-2172