Add:
        bitshift/assets.py, static/sass/404.sass
                -Add `syntax_highlight()` and style rules to perform syntax
                highlighting on 404 error messages; used in
                `templates/error404.html`.

        templates
                -Add a `Jinja` expression to select a random "404" message from
                a sequence.

Add:
        app.py
                -Remove hard-coded routes for files in the application's "root"
                (`static/`) directory; redefined Flask's `static_url_path`
                accordingly. Files can now be directly accessed by URL.

        bitshift/assets.py
                -Remove the `static/` prepended to all resource paths.