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()

test/JsonParser/StaticJsonObject.cpp

@@ -0,0 +1,69 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2018
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("deserializeJson(StaticJsonObject&)") {
+  SECTION("BufferOfTheRightSizeForEmptyObject") {
+    StaticJsonObject<JSON_OBJECT_SIZE(0)> obj;
+    char input[] = "{}";
+
+    bool success = deserializeJson(obj, input);
+
+    REQUIRE(success == true);
+  }
+
+  SECTION("TooSmallBufferForObjectWithOneValue") {
+    StaticJsonObject<JSON_OBJECT_SIZE(1) - 1> obj;
+    char input[] = "{\"a\":1}";
+
+    bool success = deserializeJson(obj, input);
+
+    REQUIRE(success == false);
+  }
+
+  SECTION("BufferOfTheRightSizeForObjectWithOneValue") {
+    StaticJsonObject<JSON_OBJECT_SIZE(1)> obj;
+    char input[] = "{\"a\":1}";
+
+    bool success = deserializeJson(obj, input);
+
+    REQUIRE(success == true);
+  }
+
+  SECTION("TooSmallBufferForObjectWithNestedObject") {
+    StaticJsonObject<JSON_OBJECT_SIZE(1) + JSON_ARRAY_SIZE(0) - 1> obj;
+    char input[] = "{\"a\":[]}";
+
+    bool success = deserializeJson(obj, input);
+
+    REQUIRE(success == false);
+  }
+
+  SECTION("BufferOfTheRightSizeForObjectWithNestedObject") {
+    StaticJsonObject<JSON_OBJECT_SIZE(1) + JSON_ARRAY_SIZE(0)> obj;
+    char input[] = "{\"a\":[]}";
+
+    bool success = deserializeJson(obj, input);
+
+    REQUIRE(success == true);
+  }
+
+  SECTION("CharPtrNull") {
+    StaticJsonObject<100> obj;
+
+    bool success = deserializeJson(obj, static_cast<char*>(0));
+
+    REQUIRE(success == false);
+  }
+
+  SECTION("ConstCharPtrNull") {
+    StaticJsonObject<100> obj;
+
+    bool success = deserializeJson(obj, static_cast<const char*>(0));
+
+    REQUIRE(success == false);
+  }
+}