R1:6229b7bd88cd

Refresh Feed Design

Summary: Refreshes feed's design a bit, adds app icons, works nicer on mobile.

Test Plan: Tested many feed stories, not sure I got them all, but seems fine.

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5673