Switched Main Directory Jump Panel to a Jump List Filter

Summary:
Sorry, I'm bad with puns

{F38258}

vs

{F38259}

It was a tough decision. We went with the latter. See chatlog today.

Test Plan: See screens

Reviewers: epriestley, chad, btrahan

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5522