Cleaning up day view sidebar css

Summary: Cleaning up day view sidebar css

Test Plan: All day events in day view sidebar should look like links, not boxes

Reviewers: chad, Blessed Reviewers, epriestley

Reviewed By: Blessed Reviewers, epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D12801