Made progress on pagination

Summary: Pagination occurs once

Test Plan: Tested on conpherences I made with myself. Lot of bugs still remain, but shows older messages in gaps of 2.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin, chad

Maniphest Tasks: T2428

Differential Revision: https://secure.phabricator.com/D5183

Conflicts:

src/applications/conpherence/controller/ConpherenceViewController.php
webroot/rsrc/js/application/conpherence/behavior-menu.js