Conpherence - make widget selector be a fun JS-based menu

Summary: Ref T3155. Also re-adds the ability to update Conpherence titles by letting user click the title and fill out a little dialogue. Also fixes a bunch of random bugs and what have you. I tried to make the javascript less mysterious by trying to code what's actually happening more explicitly. Still a work in progress all over the place but a good stopping point for feedback.

Test Plan: played around with Conpherence. In particular, went to /conpherence/ and re-sized and went to /conpherence/X/ and re-sized. Also loaded up my no conpherneces user.

Reviewers: epriestley

Reviewed By: epriestley

CC: chad, aran, Korvin

Maniphest Tasks: T3155

Differential Revision: https://secure.phabricator.com/D6022