Allow a view to override the brand (esp. for conference splash pages),
Use the app name link for the admin control panel,
use the conference short title for end user content within a conference,
fall back to the app name link.
Visually, there are two substantial changes:
(1) the conference title (or short title) serves as the brand when viewing
conference content;
(2) the short title isn't shown redundantly on the navbar and the top of the
sidebar when editing a conf.
