If a url is present in stream description, it will be
rendered as a clickable link under /streams page.
Tweaked by tabbott to use the separate rendered_description element to
avoid duplicate rendering and to live-update.
Fixes#1435.
This adds a button to #subsciption page called "View Stream"
that narrows the user to that particular stream.
This fix involves typical changes to JS/CSS to add new features,
and we also add a "preview_url" field to the sub object in
stream_data.js.
Fixes#3878
This restyles the subscriber list in the subscription settings panel to
have a more padded and lighter aesthetic and replaces the dark red
buttons with transparent buttons that have only red borders and inner
text.
Change the remaining "Admin settings" with a button, namely
changing a stream's privacy, to instead be a "[Change]" link
opening a confirmation modal.
Fixes: #3493.