In stream deactivation modal, make "stream_name" a template variable,
rather than patching stream name to modal header in javascript.
Add tests for deactivation stream modal.
This refactors and fixes unicode issues where entities don't display
properly due to being a special character that seems to be rendered
incorrectly in a non-deterministic way every time.
This either removes aria-hidden=true assignments from buttons with
text, or adds a span to only hide the 'x' symbol rather than the
button for closing buttons.
This removes the old base button style which was a blue button and
kills the unnecessary .white class which was essentially just acting as
the new button base.
This then removes all references throughout the settings/subscriptions
pages to those button styles.
This also fixes the strange button styles that changed the :hover and
:active opacity to 0.05 which led to unpredictable results on various
backgrounds.