add copyright notice

81d2dd58 · Florian Fischer · 69c2dc5a · 81d2dd58
Commit 81d2dd58 authored Jan 15, 2019 by Florian Fischer
--- a/LICENSE
+++ b/LICENSE
+Copyright (c) 2018-2019 Florian Fischer et al.
+                    
                    GNU GENERAL PUBLIC LICENSE
                       Version 3, 29 June 2007