Replaced printTo() with serializeJson()

* Added `serializeJson()` and `serializeJsonPretty()`
* Added `measureJson()` and `measureJsonPretty()`
* Removed `printTo()` and `prettyPrintTo()`
* Removed `measureLength()` and `measurePrettyLength()`

test/CMakeLists.txt

@@ -69,6 +69,7 @@ add_subdirectory(IntegrationTests)
 add_subdirectory(JsonArray)
 add_subdirectory(JsonObject)
 add_subdirectory(JsonParser)
+add_subdirectory(JsonSerializer)
 add_subdirectory(JsonVariant)
 add_subdirectory(JsonWriter)
 add_subdirectory(Misc)