Make the clock mo-pretty

Summary: Also swap out orange for red in telling_time_2 so the text isn't as light.

Test Plan: Load telling_time_0.5, telling_time, and telling_time_2 in local mode, take all the hints, answer, etc.

Reviewers: joel

Reviewed By: joel

CC: alpert

Differential Revision: http://phabricator.khanacademy.org/D6122