allow get_filenames to follow symlinks

Author: colethorsen

system/Helpers/filesystem_helper.php

@@ -209,7 +209,7 @@ function get_filenames(
 
         try {
             foreach (new RecursiveIteratorIterator(
-                new RecursiveDirectoryIterator($sourceDir, RecursiveDirectoryIterator::SKIP_DOTS),
+                new RecursiveDirectoryIterator($sourceDir, RecursiveDirectoryIterator::SKIP_DOTS | FilesystemIterator::FOLLOW_SYMLINKS),
                 RecursiveIteratorIterator::SELF_FIRST
             ) as $name => $object) {
                 $basename = pathinfo($name, PATHINFO_BASENAME);