Extracted StringReader and StringWriter from JsonParser

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

include/ArduinoJson/Data/Encoding.hpp

@@ -0,0 +1,42 @@
+// 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 "../Print.hpp"
+
+namespace ArduinoJson {
+namespace Internals {
+
+class Encoding {
+ public:
+  // Optimized for code size on a 8-bit AVR
+  static char escapeChar(char c) {
+    const char *p = escapeTable(false);
+    while (p[0] && p[1] != c) {
+      p += 2;
+    }
+    return p[0];
+  }
+
+  // Optimized for code size on a 8-bit AVR
+  static char unescapeChar(char c) {
+    const char *p = escapeTable(true);
+    for (;;) {
+      if (p[0] == '\0') return c;
+      if (p[0] == c) return p[1];
+      p += 2;
+    }
+  }
+
+ private:
+  static const char *escapeTable(bool excludeIdenticals) {
+    return &"\"\"\\\\b\bf\fn\nr\rt\t"[excludeIdenticals ? 4 : 0];
+  }
+};
+}
+}