DirectHttp: added 503 support

git-svn-id: svn://svn.jdownloader.org/jdownloader/trunk@21492 ebf7c1c2-ba36-0410-9fe8-c592906822b4
Updated italiano Translation

git-svn-id: svn://svn.jdownloader.org/jdownloader/trunk@21493 ebf7c1c2-ba36-0410-9fe8-c592906822b4