* switch to composer for qrcode and otp dependencies

* move most OTP-related stuff into userhelper
* remove old phpqrcode and otphp libraries

vendor/chillerlan/php-settings-container/examples/simple.php

@@ -0,0 +1,30 @@
+<?php
+/**
+ * @filesource   simple.php
+ * @created      28.08.2018
+ * @author       smiley <smiley@chillerlan.net>
+ * @copyright    2018 smiley
+ * @license      MIT
+ */
+
+namespace chillerlan\SettingsExamples;
+
+use chillerlan\Settings\SettingsContainerAbstract;
+
+require_once __DIR__.'/../vendor/autoload.php';
+
+class MyContainer extends SettingsContainerAbstract{
+	protected $foo;
+	protected $bar;
+}
+
+/** @var \chillerlan\Settings\SettingsContainerInterface $container */
+$container = new MyContainer(['foo' => 'what']);
+$container->bar = 'foo';
+
+var_dump($container->toJSON()); // -> {"foo":"what","bar":"foo"}
+
+// non-existing properties will be ignored:
+$container->nope = 'what';
+
+var_dump($container->nope); // -> NULL