Use wide links only for line and blame-prev in Diffusion

Summary: D1701 disallowed me selecting authors and revisions by mouse, grrr.

Test Plan: View file, hover over <th>, click.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, epriestley

Differential Revision: https://secure.phabricator.com/D1736