Add Balanced Payments API

Summary: Adds the Balanced PHP API to externals/. Ref T2787.

Test Plan: Used in next diff.

Reviewers: btrahan, chad

Reviewed By: chad

CC: aran, aurelijus

Maniphest Tasks: T2787

Differential Revision: https://secure.phabricator.com/D5764

externals/restful/src/RESTful/Exceptions/Base.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace RESTful\Exceptions;
+
+/**
+ * Base class for all RESTful\Exceptions.
+ */
+class Base extends \Exception
+{
+}

externals/restful/src/RESTful/Exceptions/HTTPError.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace RESTful\Exceptions;
+
+/**
+ * Indicates an HTTP level error has occurred. The underlying HTTP response is
+ * stored as response member. The response payload fields if any are stored as
+ * members of the same name.
+ *
+ * @see \Httpful\Response
+ */
+class HTTPError extends Base
+{
+    public $response;
+
+    public function __construct($response)
+    {
+        $this->response = $response;
+        $this->_objectify($this->response->body);
+    }
+
+    protected function _objectify($fields)
+    {
+        foreach ($fields as $key => $val) {
+            $this->$key = $val;
+        }
+    }
+}

externals/restful/src/RESTful/Exceptions/MultipleResultsFound.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace RESTful\Exceptions;
+
+/**
+ * Indicates that a query unexpectedly returned multiple results when at most
+ * one was expected.
+ */
+class MultipleResultsFound extends Base
+{
+}

externals/restful/src/RESTful/Exceptions/NoResultFound.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace RESTful\Exceptions;
+
+/**
+ * Indicates that a query unexpectedly returned no results.
+ */
+class NoResultFound extends Base
+{
+}