Extracted StringReader and StringWriter from JsonParser

Split `Internals/` folder into `Data/`, `Deserialization/`, `Serialization/`

include/ArduinoJson/Serialization/DynamicStringBuilder.hpp

@@ -0,0 +1,33 @@
+// Copyright Benoit Blanchon 2014-2016
+// MIT License
+//
+// Arduino JSON library
+// https://github.com/bblanchon/ArduinoJson
+// If you like this project, please add a star!
+
+#pragma once
+
+#include "../Data/StringFuncs.hpp"
+#include "../Print.hpp"
+
+namespace ArduinoJson {
+namespace Internals {
+
+// A Print implementation that allows to write in a String
+template <typename TString>
+class DynamicStringBuilder : public Print {
+ public:
+  DynamicStringBuilder(TString &str) : _str(str) {}
+
+  virtual size_t write(uint8_t c) {
+    StringFuncs<TString>::append(_str, static_cast<char>(c));
+    return 1;
+  }
+
+ private:
+  DynamicStringBuilder &operator=(const DynamicStringBuilder &);
+
+  TString &_str;
+};
+}
+}