Add remaining project files (exclude ignored folders)

vendor/markbaker/matrix/classes/src/Exception.php

@@ -0,0 +1,13 @@
+<?php
+
+/**
+ * Exception.
+ *
+ * @copyright  Copyright (c) 2013-2018 Mark Baker (https://github.com/MarkBaker/PHPMatrix)
+ * @license    https://opensource.org/licenses/MIT    MIT
+ */
+namespace Matrix;
+
+class Exception extends \Exception
+{
+}