Don't use JsonBuffer to create or parse objects and arrays.

* Added DynamicJsonArray and StaticJsonArray
* Added DynamicJsonObject and StaticJsonObject
* Added DynamicJsonVariant and StaticJsonVariant
* Added deserializeJson()
* Removed JsonBuffer::parseArray(), parseObject() and parse()
* Removed JsonBuffer::createArray() and createObject()

src/ArduinoJson/DynamicJsonVariant.hpp

@@ -0,0 +1,40 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2018
+// MIT License
+
+#pragma once
+
+#include "DynamicJsonBuffer.hpp"
+#include "JsonVariant.hpp"
+
+namespace ArduinoJson {
+
+class DynamicJsonVariant : public JsonVariant {
+  DynamicJsonBuffer _buffer;
+
+ public:
+  DynamicJsonVariant() : JsonVariant() {}
+
+  template <typename T>
+  DynamicJsonVariant& operator=(const T& value) {
+    _buffer.clear();
+    JsonVariant::operator=(value);
+    return *this;
+  }
+
+  template <typename T>
+  DynamicJsonVariant& operator=(const T* value) {
+    _buffer.clear();
+    JsonVariant::operator=(value);
+    return *this;
+  }
+
+  DynamicJsonBuffer& buffer() {
+    return _buffer;
+  }
+
+  size_t memoryUsage() const {
+    return _buffer.size() + sizeof(JsonVariant);
+  }
+};
+}  // namespace ArduinoJson