* Put meta related functions in src/input/meta.c
* Merge vlc_meta_engine.h and vlc_meta.h

Album art stuff is still broken, but I need to go now :)

[PATCH] mosaic improvement: user-defined offsets for substreams by Thomas Parmelan. +fixes for svn trunk

* meta reader : read directly from the file, should be made from the demux.
  Examples: taglib, id3tag
* meta fetcher : use web services to get meta, either from the current ones.
  Called only if we don't have the tags after using the meta readers
* art finder : find the URL of the suitable album art. Called according to the
  art policy
* art downloader : used to retrieve the art from special locations. Not needed
  if art is available directly from an URL.
  Examples: APIC ID3 tag reader

Features to add to it:
* Parse more meta than artist/title :)
* Fetch duration for Vorbis files
* Fetch album art in ID3v2 (APIC frames)
* Write back tags to file

Unfortunately, it only works for files, so it can't replace libid3tag

Add input_ItemAddOptionNoDup (unused at the moment)
+ free warning fix

This removes useless wakeups and improves hotkeys reactivity

  p_libvlc->b_die
  Not implemented for OS X as I am not sure, please check if it is feasible.
* Don't run the dummy interface

Add low priority "folder" meta_engine. Will look for files named "Folder.jpg" (Windows), "AlbumArtSmall.jpg" (Windows) or ".folder.png" (Linux) to use as album art.

Add an "album art download policy" (--album-art) option. I now have to do another commit to enfore this policy (album art isn't downloaded at all atm)

Start of meta engine stuff. src/input/input.c needs to be fixed a bit. I'll finish it today. @zorglub: now you have to use the psz_arturl meta to display stuff in the interface.

* Fixes to dialog singletons
* Forgotten files (definitions of aout_Visual*, unimplemented at the moment)

Make some sttings persistent