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/docs/usage/token-generation.rst

@@ -0,0 +1,64 @@
+===========================
+Generate Capability Tokens
+===========================
+
+`Twilio Client <http://www.twilio.com/api/client>`_ allows you to make and recieve connections in the browser. You can place a call to a phone on the PSTN network, all without leaving your browser. See the `Twilio Client Quickstart <http:/www.twilio.com/docs/quickstart/client>`_ to get up and running with Twilio Client.
+
+Capability tokens are used by `Twilio Client <http://www.twilio.com/api/client>`_ to provide connection security and authorization. The `Capability Token documentation <http://www.twilio.con/docs/tokens>`_ explains indepth the purpose and features of these tokens.
+
+:php:class:`Services_Twilio_Capability` is responsible for the creation of these capability tokens. You'll need your Twilio AccountSid and AuthToken.
+
+.. code-block:: php
+
+    require('/path/to/twilio-php/Services/Twilio/Capability.php');
+
+    $accountSid = "AC123123";
+    $authToken = "secret";
+
+    $capability = new Services_Twilio_Capability($accountSid, $authToken);
+
+
+Allow Incoming Connections
+==============================
+
+Before a device running `Twilio Client <http://www.twilio.com/api/client>`_ can recieve incoming connections, the instance must first register a name (such as "Alice" or "Bob"). The :php:meth:`allowCclientIncoming` method adds the client name to the capability token.
+
+.. code-block:: php
+
+    $capability->allowClientIncoming("Alice");
+
+
+Allow Outgoing Connections
+==============================
+
+To make an outgoing connection from a `Twilio Client <http://www.twilio.com/api/client>`_ device, you'll need to choose a `Twilio Application <http://www.twilio.com/docs/api/rest/applications>`_ to handle TwiML URLs. A Twilio Application is a collection of URLs responsible for outputing valid TwiML to control phone calls and SMS.
+
+.. code-block:: php
+
+    $applicationSid = "AP123123"; // Twilio Application Sid
+    $capability->allowClientOutgoing($applicationSid);
+
+:php:meth:`allowClientOutgoing` accepts an optional array of parameters. These parameters will be passed along when Twilio requests TwiML from the application.
+
+.. code-block:: php
+
+    $applicationSid = "AP123123";    // Twilio Application Sid
+    $params = array("Foo" => "Bar"); // Parameters to be passed
+    $capability->allowClientOutgoing($applicationSid, $params);
+
+
+Generate a Token
+==================
+
+.. code-block:: php
+
+    $token = $capability->generateToken();
+
+By default, this token will expire in one hour. If you'd like to change the token expiration time, :php:meth:`generateToken` takes an optional argument which specifies `time to live` in seconds.
+
+.. code-block:: php
+
+    $token = $capability->generateToken(600);
+
+This token will now expire in 10 minutes.
+