charset the HTML pages will be transformed into (default no transform,
   ie. UTF-8). Call vlc_fix_readdir_charset whenever necessary, the
   http intf should now work under Mac OS X with non-ascii filenames.
   When using the 'add' command (MVLC_ADD), add an extra paramater 'name'
   besides 'mrl' to specify which name to use in the playlist.