add sabre (1.8.x) via composer in the !@#$ place it wants to be

vendor/autoload.php

@@ -0,0 +1,7 @@
+<?php
+
+// autoload.php @generated by Composer
+
+require_once __DIR__ . '/composer' . '/autoload_real.php';
+
+return ComposerAutoloaderInit4d84580b3010f36341ea4e8d04bc8eab::getLoader();