Add COPYING, AUTHORS, and clean-up all source files

Add:
- text of GNU GPLv3 in COPYING
- list of authors in AUTHORS
Clean-up all source files, ready for applying copyright and licence notices

AUTHORS

@@ -0,0 +1,99 @@
+Original package authors:
+David Lange
+Anders Ryd
+
+Current authors / maintainers:
+John Back
+Michal Kreps
+Thomas Latham
+
+Contributors:
+Abi Soffer
+Adlene Hicheur
+Ajit Kurup
+Akimasa Ishikawa
+Aleksandr Berezhnoi
+Aleksei Luchinsky
+Alexander Popov
+Alexei Dvoretskii
+Alexei Volk
+Anatoli Likhoded
+Andrei Gritsan
+Andrew Crocombe
+Andrii Verbytskyi
+Anna Danilina
+Aurelien Martens
+Bob Cahn
+Brian Hamilton
+Christoph Langenbruch
+Clara Remon
+Daniel Craik
+David Cote
+David Grellscheid
+David Kirkby
+David Loh
+Denis Dujmic
+Diego Martinez Santos
+Edward Chen
+Elisabeth Niel
+Eric Conte
+Fernando Martinez-Vidal
+Florence Ranjard
+Francesca Di Lodovico
+Francesco Sandrelli
+Frank Wuerthwein
+Frederic Dreyer
+Gerhard Raven
+Gloria Corti
+Greig Cowan
+Jack Wimberley
+Jan Strube
+Jane Tinslay
+Jeff Berryhill
+Jeremy Dalseno
+Jim Hunt
+Jim Libby
+Jochen Dingfelder
+Joe Izen
+Jordi Garra Tico
+Josh Thompson
+Karen Gibson
+Konstantin Toms
+Liaoyuan Dong
+Luis Miguel Garcia Martin
+Marcello Rotondo
+Marcin Chrzaszcz
+Marco Bomben
+Marco Gersabeck
+Marcos Romero Lamas
+Mark Smith
+Mark Whitehead
+Mark Ian Williams
+Martin Simard
+Matt Graham
+Maurizio Pierini
+Max Baak
+Michael Sigamani
+Natalia Kuznetsova
+Nick Brook
+Nikolai Nikitin
+Patrick Robbe
+Pavel Reznicek
+Peter Richardson
+Phil Strother
+Ricardo Faccini
+Richard Tesarek
+Romulus Godang
+Ryan Newcombe
+Sheila McLachlin
+Simon Patton
+Sophie Versille
+Stephane Willocq
+Steve Sekula
+Sven Menke
+Thomas Blake
+Tomas Pilar
+Veronika Chobanova
+Wells Wulsin
+Will Reece
+William Sutcliffe