Highlight today on Calendar/Conpherence

Summary: Highlights which day is today on the calendar list in conpherence. Fixes T3254

Test Plan: Made sure today was Tuesday.

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T3254

Differential Revision: https://secure.phabricator.com/D6065