R1:68ab9b2642b8

Switch fluid to fixed on PHUITwoColumnView

Summary: We don't ever set fluid, since it already is fluid, also no CSS. Add an actual fixed version.

Test Plan: For use in Instances.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D18336