Added StaticJsonDocument and DynamicJsonDocument.

Removed StaticJsonArray and DynamicJsonArray.
Removed StaticJsonObject and DynamicJsonObject.
Removed StaticJsonVariant and DynamicJsonVariant.

src/ArduinoJson/JsonObject.hpp

@@ -229,6 +229,11 @@ class JsonObject : public Internals::ReferenceType,
     return instance;
   }
 
+  template <typename Visitor>
+  void visit(Visitor visitor) const {
+    return visitor.acceptObject(*this);
+  }
+
  private:
   // Returns the list node that matches the specified key.
   template <typename TStringRef>