Make the dependency on stdbuf optional for everything but notify

src/Exception/DependencyException.php

@@ -0,0 +1,11 @@
+<?php
+/**
+ * Copyright (c) 2016 Robin Appelman <icewind@owncloud.com>
+ * This file is licensed under the Licensed under the MIT license:
+ * http://opensource.org/licenses/MIT
+ */
+
+namespace Icewind\SMB\Exception;
+
+class DependencyException extends Exception {
+}