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/Settings.php

@@ -0,0 +1,12 @@
+<?php
+
+namespace RESTful;
+
+/**
+ * Settings.
+ *
+ */
+class Settings
+{
+    const VERSION = '0.1.7';
+}