added awareness of file permissions

Files as listed using the "direct" parameter now need to be readable to the
webserver to be part of the list.

darcs-hash:20080404171207-2b4f5-c72e39a8fa30b2629cef0330b1b6d1a6ce23413d.gz

syntax.php

@@ -319,6 +319,8 @@ class syntax_plugin_filelist extends DokuWiki_Syntax_Plugin {
             	$mid = str_replace('/', ':', substr($filename, strlen($this->mediadir)));
             	$perm = auth_quickaclcheck($mid);
       			if ($perm < AUTH_READ) continue;    
+            } else {                         // exclude not readable files
+            	if (!is_readable($filename)) continue;
             }
             
             array_push($files['names'], $filename);