Add GPLv3 and copyright header

blocks/GenericArgsSubstitutor.cs

@@ -1,4 +1,23 @@
-using System.Collections.Generic;
+/*
+    Copyright (C) 2011-2012 de4dot@gmail.com
+
+    This file is part of de4dot.
+
+    de4dot 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.
+
+    de4dot 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 de4dot.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+using System.Collections.Generic;
 using dot10.DotNet;
 
 namespace de4dot.blocks {