Re-license almost all of libVLC and libVLCcore to LGPLv2.1+

This move was authorized by the developers, either:
 - by e-mail,
 - by vote at the VideoLAN Dev Days 2011,
 - on the license website,
 - in a contract, oral or written.
No objection was raised, so far.

The developers agreeing are:
  Justus Piater
  Alexis Ballier
  Alexander Bethke
  Mohammed Adnène Trojette
  Alex Converse
  Alexey Sokolov
  Alexis de Lattre
  Andre Pang
  Anthony Loiseau
  Cyril Deguet
  André Weber
  Boris Dorès
  Brieuc Jeunhomme
  Benjamin Drung
  Hugo Beauzée-Luyssen
  Benoit Steiner
  Benjamin Pracht
  Bernie Purcell
  Przemyslaw Fiala
  Arnaud de Bossoreille de Ribou
  Brad Smith
  Nick Briggs
  Christopher Rath
  Christophe Courtaut
  Christopher Mueller
  Clement Chesnin
  Andres Krapf
  Damien Fouilleul
  David Flynn
  Sebastien Zwickert
  Antoine Cellerier
  Jérôme Decoodt
  Jérome Decoodt
  Dylan Yudaken
  Eduard Babayan
  Eugenio Jarosiewicz
  Elliot Murphy
  Eric Petit
  Erwan Tulou
  Etienne Membrives
  Ludovic Fauvet
  Fabio Ritrovato
  Tobias Güntner
  Jakub Wieczorek
  Frédéric Crozat
  Francois Cartegnie
  Laurent Aimar
  Florian G. Pflug
  Felix Paul Kühne
  Frank Enderle
  Rafaël Carré
  Simon Latapie
  Gildas Bazin
  Geoffroy Couprie
  Julien / Gellule
  Gildas Bazin
  Arnaud Schauly
  Toralf Niebuhr
  Vicente Jimenez Aguilar
  Derk-Jan Hartman
  Henri Fallon
  Ilkka Ollakka
  Olivier Teulière
  Rémi Duraffort
  Jakob Leben
  Jean-Baptiste Kempf
  Jean-Paul Saman
  Jean-Philippe Grimaldi
  Jean-François Massol
  Gaël Hendryckx
  Jakob Leben
  Jean-Marc Dressler
  Jai Menon
  Johan Bilien
  Johann Ransay
  Joris van Rooij
  JP Dinger
  Jean-Philippe André
  Adrien Grand
  Juha Jeronen
  Juho Vähä-Herttua
  Kaarlo Raiha
  Kaarlo Raiha
  Kamil Baldyga
  Keary Griffin
  Ken Self
  KO Myung-Hun
  Pierre Ynard
  Filippo Carone
  Loïc Minier
  Luca Barbato
  Lucas C. Villa Real
  Lukas Durfina
  Adrien Maglo
  Marc Ariberti
  Mark Lee
  Mark Moriarty
  Martin Storsjö
  Christophe Massiot
  Michel Kaempf
  Marian Ďurkovič
  Mirsal Ennaime
  Carlo Calabrò
  Damien Lucas
  Naohiro Koriyama
  Basos G
  Pierre Baillet
  Vincent Penquerc'h
  Olivier Aubert
  Pankaj Yadav
  Paul Corke
  Pierre d'Herbemont
  Philippe Morin
  Antoine Lejeune
  Michael Ploujnikov
  Jean-Marc Dressler
  Michael Hanselmann
  Rafaël Carré
  Ramiro Polla
  Rémi Denis-Courmont
  Renaud Dartus
  Richard Shepherd
  Faustino Osuna
  Arnaud Vallat
  Rob Jonson
  Robert Jedrzejczyk
  Steve Lhomme
  Rocky Bernstein
  Romain Goyet
  Rov Juvano
  Sam Hocevar
  Martin T. H. Sandsmark
  Sebastian Birk
  Sébastien Escudier
  Vincent Seguin
  Fabio Ritrovato
  Sigmund Augdal Helberg
  Casian Andrei
  Srikanth Raju
  Hannes Domani
  Stéphane Borel
  Stephan Krempel
  Stephan Assmus
  Tony Castley
  Pavlov Konstantin
  Eric Petit
  Tanguy Krotoff
  Dennis van Amerongen
  Michel Lespinasse
  Can Wu
  Xavier Marchesini
  Sébastien Toque
  Christophe Mutricy
  Yoann Peronneau
  Yohann Martineau
  Yuval Tze
  Scott Caudle
  Clément Stenac

It is possible, that some minor piece of code was badly tracked, for
some reasons (SVN, mainly) or that some small developers did not answer.
However, as an "œuvre collective", defined as in "CPI 113-2 alinéa 3",
and seeing "Cour. Cass. 17 Mai 1978", and seeing that the editor and
the very vast majority of developers have agreed (> 99.99% of the code,
> 99% of developers), we are fine here.

This should help Doxygen parse VLC headers, and generally makes headers
easier to read. LibVLC already uses a similar approach.

(cherry picked from commit b5687139f9ac84a7bdf03d9a9612950c43fe6ec2)

if( bla ) free( bla ); => free( bla );

* include/vlc_url.h: vlc_UrlParse(): forbid use of '/' in login or password. Fixes use of URLs like "http://www.lemonde.fr/web/video/0,47-0@2-3210,54-913109@51-891944,0.html".

 We use vlc_UrlParse for "URL" without protocol... so it was using a part of
the URL as a protocol if it found ":/". Ensure to extract only valid protocol
at least.

* libvlc sources and plugins now define __LIBVLC__ and headers exported to
  plugins (ie, include/vlc_*.h) check for this
* libvlc sources use the value of the "libvlc" component in vlc-config instead
  of vlc
* Apply flags directly to "libvlc" in configure.ac - might temporarily break win32 :)

* Headers in include must contain the structures and prototypes needed
  by the plugins and should be named vlc_*.
* Headers in include/vlc must contain the structures and prototypes
  needed by external libvlc clients

* Moved and renamed some things in headers. 
   - Removed vlc_cpu.h, vlc_error.h (merged in vlc_common)
   - Removed snapshot.h (merged in vlc_vout.h)
   - Removed vlc_spu.h (merged in vlc_osd.h)
   - Removed intf_eject.h and vlc_interaction.h (merged in vlc_interface)
   - Moved all internal headers to src
   - Merged vlc_video.h and video_output.h and move private things to src
   - Removed vlc/intf.h, vlc/aout.h, vlc/vout.h, vlc/decoder.h and vlc/input.h
     (meta headers for use in modules, and often implying too large 
     dependencies)
* Removed some useless dependencies
* Unexported a bunch of functions and structures used only in src/
  (--> Still some work here)
* Finally made input_thread_t and input_source_t (mostly) private. 
  Added input_GetItem to fetch the input_item of an input_thread
* Cleaned up deprecated entries in vlc_symbols.h and bumped up symbol 
  prefix

This commit has a 99% probability of breaking the build, 0.1% of killing
your cat and 0% of getting you hot chicks.

- Replace crap URL escaping with URL encoding, which is what we really need

   crashing with strings as simple as "/toto", but all in all the entire
   function seems very wrong to me, see the next mail.

- Rename decode_encoded_URI as unescape_URI as it really is what is done.

(ie. all characters from the Basic Multilingual Plane from Unicode)