* switch to composer for qrcode and otp dependencies

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

vendor/composer/autoload_classmap.php

@@ -0,0 +1,10 @@
+<?php
+
+// autoload_classmap.php @generated by Composer
+
+$vendorDir = dirname(dirname(__FILE__));
+$baseDir = dirname($vendorDir);
+
+return array(
+    'Composer\\InstalledVersions' => $vendorDir . '/composer/InstalledVersions.php',
+);