Added copylight text.

Refined examples.

example/cpp03/class_intrusive.cpp

@@ -1,10 +1,28 @@
+// MessagePack for C++ example
+//
+// Copyright (C) 2008-2015 FURUHASHI Sadayuki and KONDO Takatoshi
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+//
+
 #include <string>
 #include <iostream>
 #include <iomanip>
 #include <sstream>
 #include <cassert>
 
-#include <msgpack.hpp>
+// msgpack.hpp is also ok
+#include <msgpack_fwd.hpp>
 
 
 class my_class {
@@ -39,6 +57,8 @@ void print(std::string const& buf) {
     std::cout << std::endl;
 }
 
+#include <msgpack.hpp>
+
 int main() {
     my_class my("John Smith", 42);
     std::stringstream ss;