Fix directories with unicode characters not being supported

libs/Tree/Builder.php

@@ -75,7 +75,7 @@ class Builder
             }
 
             if ($file->isDir()) {
-                $title = static::removeSortingInformations($file->getFilename());
+                $title = DauxHelper::slug(static::removeSortingInformations($file->getFilename()));
                 $new = new Directory($node, $title, $file);
                 $new->setName(static::getName($file->getPathName()));
                 $new->setTitle(str_replace('_', ' ', static::removeSortingInformations($new->getName())));