Refactor API files: replace require with require_once for improved file inclusion

api/template/get.php

@@ -5,7 +5,7 @@ if (!isset($internal)) {
     define("API_DIR", "../");
 }
 // Load Main Library
-require API_DIR . "api.php";
+require_once API_DIR . "api.php";
 $api = new gbAPI(false, $internal);
 
 // Get Template