R1:8e7e999cc34b

Slightly better spacing, colors on ProjectCards

Summary: Fixes transparent background images, removes "checkered". Better spacing for tags.

Test Plan:
Upload a transparent logo, hover over project.

{F1093753}

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D15188