R1:ebc3811bed3f

Cleaner Countdown widget UI

Summary: Adds the launch date, normalize spacing a bit.

Test Plan:
Test a normal and embeded countdowns.

{F670199}

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D13740