LICENSE: fix a few years

LICENSE

@@ -2,15 +2,15 @@ MIT/X Consortium License
 
 © 2014-2018 Hiltjo Posthuma <hiltjo at codemadness dot org>
 © 2018 Devin J. Pohly <djpohly at gmail dot com>
-© 2017-2017 Quentin Rameau <quinq at fifth dot space>
+© 2014-2017 Quentin Rameau <quinq at fifth dot space>
 © 2009-2012 Aurélien APTEL <aurelien dot aptel at gmail dot com>
-© 2009 Anselm R Garbe <garbeam at gmail dot com>
+© 2008-2017 Anselm R Garbe <garbeam at gmail dot com>
 © 2012-2017 Roberto E. Vargas Caballero <k0ga at shike2 dot com>
 © 2012-2016 Christoph Lohmann <20h at r-36 dot net>
 © 2013 Eon S. Jeon <esjeon at hyunmu dot am>
 © 2013 Alexander Sedov <alex0player at gmail dot com>
 © 2013 Mark Edgar <medgar123 at gmail dot com>
-© 2013 Eric Pruitt <eric.pruitt at gmail dot com>
+© 2013-2014 Eric Pruitt <eric.pruitt at gmail dot com>
 © 2013 Michael Forney <mforney at mforney dot org>
 © 2013-2014 Markus Teich <markus dot teich at stusta dot mhn dot de>
 © 2014-2015 Laslo Hunhold <dev at frign dot de>