Add SMS support

Summary:
Provides a working SMS implementation with support for Twilio.

This version doesn't really retry if we get any gruff at all. Future versions should retry.

Test Plan: used bin/sms to send messages and look at them.

Reviewers: chad, epriestley

Reviewed By: epriestley

Subscribers: aurelijus, epriestley, Korvin

Maniphest Tasks: T920

Differential Revision: https://secure.phabricator.com/D8930

externals/twilio-php/Services/Twilio/Rest/SmsMessages.php

@@ -0,0 +1,18 @@
+<?php
+
+class Services_Twilio_Rest_SmsMessages
+    extends Services_Twilio_ListResource
+{
+    public function __construct($client, $uri) {
+        $uri = preg_replace("#SmsMessages#", "SMS/Messages", $uri);
+        parent::__construct($client, $uri);
+    }
+
+    function create($from, $to, $body, array $params = array()) {
+        return parent::_create(array(
+            'From' => $from,
+            'To' => $to,
+            'Body' => $body
+        ) + $params);
+    }
+}