update LICENSE: major contributors

LICENSE

@@ -1,8 +1,11 @@
 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>
 © 2009-2012 Aurélien APTEL <aurelien dot aptel at gmail dot com>
 © 2009 Anselm R Garbe <garbeam at gmail dot com>
-© 2012-2016 Roberto E. Vargas Caballero <k0ga at shike2 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>