Added 'nothing-to-do' semantic for mime-helpers: Point back by symlink. Added helper/text=x-shellscript to demonstrate this. Made external mime-helpers work: registering, calling. Remember absolut path, call mime_type() correctly. Started to propagate errors from _run_mime_handler() to unpack(). mime(): In SLES11 we get 'text/plain charset=utf-8' without semicolon.