Remove inline gutter in Pholio

Summary: This greatly simplifies inline comments while retaining their functionality. This is probably not where we want to end up, but will let us figure out what we're doing with the stage without worrying about inlines.

Test Plan: See screenshots.

Reviewers: chad

Reviewed By: chad

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D9537