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

Not thorougly tested. Olivier reverts this commit without hesitation if it breaks your stuffs

Put the add button in the playlist standard panel
Remove duplicated code for playlist widgets

Add button in playlist widget