Added GPL comment at top of file.

Main.pas

@@ -1,3 +1,20 @@
+(* Copyright (c) 2017 by Stefan Vorkoetter
+
+   This file is part of PiTabDashboard.
+
+   PiTabDashboard 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.
+
+   PiTabDashboard 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 PiTabDashboard. If not, see <http://www.gnu.org/licenses/>. *)
+
 unit Main; // vim:sw=2:
 
 {$mode delphi}