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/DynamicJsonArray.hpp

@@ -0,0 +1,27 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2018
+// MIT License
+
+#pragma once
+
+#include "DynamicJsonBuffer.hpp"
+#include "JsonArray.hpp"
+
+namespace ArduinoJson {
+class DynamicJsonArray : public JsonArray {
+  DynamicJsonBuffer _buffer;
+
+ public:
+  DynamicJsonArray() : JsonArray(&_buffer) {}
+  DynamicJsonArray(size_t capacity)
+      : JsonArray(&_buffer), _buffer(capacity - sizeof(JsonArray)) {}
+
+  size_t memoryUsage() const {
+    return _buffer.size() + sizeof(JsonArray);
+  }
+
+  DynamicJsonBuffer& buffer() {
+    return _buffer;
+  }
+};
+}  // namespace ArduinoJson