chore: licensing and copyright stuff

ui/mainscreen/mainscreen.go

@@ -1,3 +1,19 @@
+// gorc project
+// Copyright (C) 2021 IllusionMan1212
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along
+// with this program; if not, see https://www.gnu.org/licenses.
+
 package mainscreen
 
 import (