We're keeping the old `apply_stylesheet_media_default` option behavior
because removing `media="screen"` from our stylesheets would completely
break our `print` stylesheet, which would now load the default the
styles defined in `application.css`.
We're also keeping the old `:mini_magick` option to process images so
existing installations don't have to install libvips on their server. We
might change it in the future.
492b2281b0