[UPDATE] Print error if vendor libs are missing

Author: TheSerapher

include/autoloader.inc.php

@@ -2,7 +2,11 @@
 (SECURITY == "*)WT#&YHfd" && SECHASH_CHECK) ? die("public/index.php -> Set a new SECURITY value to continue") : 0;
 $defflip = (!cfip()) ? exit(header('HTTP/1.1 401 Unauthorized')) : 1;
 
-require_once(INCLUDE_DIR . '/../vendor/autoload.php');
+if (file_exists(INCLUDE_DIR . '/../vendor/autoload.php')) {
+  require_once(INCLUDE_DIR . '/../vendor/autoload.php');
+} else {
+  die("Unable to load vendor libraries, please run `php composer.phar install` in root folder.");
+}
 
 // Default classes
 require_once(INCLUDE_DIR . '/lib/KLogger.php');