Remove duplicate slashes in autoloader path

Author: hctom

src/Handler.php

@@ -175,6 +175,8 @@ public function generateAutoload() {
    * @return string
    */
   protected function autoLoadContents($relativeVendorPath) {
+    $relativeVendorPath = rtrim($relativeVendorPath, '/');
+
     $autoloadContents = <<<EOF
 <?php