Make update-po

prepend argv[0] to libvlc_new parameters

mediacontrol_new API

that users of the API can simply pass parameters

 * Secondary queue items now have a b_fetch_art flag
 * You can use the playlist_AskForArtEnqueue function to ask for art from an interface. This will enqueue at the begining of the secondary queue
 * other stuff which i don't remember :)
 * (fix issues with previous (and unrelated) DIR_SEP commit)

* 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