Add os.chdir and os.setenv to d8. Move system() to os.system().

src/d8-windows.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 24 matching lines @@
 namespace v8 {
 
 
 Handle<Value> Shell::System(const Arguments& args) {
   Handle<String> error_message =
       String::New("system() is not yet supported on your OS");
   return ThrowException(error_message);
 }
 
 
+Handle<Value> Shell::ChangeDirectory(const Arguments& args) {
+  Handle<String> error_message =
+      String::New("chdir() is not yet supported on your OS");
+  return ThrowException(error_message);
+}
+
+
 }  // namespace v8