Make Notifications Realtime

Summary:
Adds the node.js Aphlict server, the flash Aphlict client, and some
supporting javascript. Built on top of - and requires - D2703 (which is still
in progress). Will likely work with no modification on top of the final
version, though.

The node server is currently run with

sudo node support/aphlict/server/aphlict_server.js

Test Plan: tested locally

Reviewers: epriestley

Reviewed By: epriestley

CC: allenjohnashton, keebuhm, aran, Korvin

Differential Revision: https://secure.phabricator.com/D2704