Massive code prolog cleanup.

samples/stringto-test.cpp

@@ -1,6 +1,24 @@
 // ***************************************************************** -*- C++ -*-
 // stringto-test.cpp
 // Test conversions from string to long, float and Rational types.
+/*
+ * Copyright (C) 2004-2021 Exiv2 authors
+ * This program is part of the Exiv2 distribution.
+ *
+ * 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 2
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, 5th Floor, Boston, MA 02110-1301 USA.
+ */
 
 #include <exiv2/exiv2.hpp>