Adjust json_object_is_type and json_object_get_type so they return json_type_null for NULL objects.
diff --git a/json_object.h b/json_object.h
index 1ee9fb0..e9898f4 100644
--- a/json_object.h
+++ b/json_object.h
@@ -79,6 +79,7 @@
* Check if the json_object is of a given type
* @param obj the json_object instance
* @param type one of:
+ json_type_null (i.e. obj == NULL),
json_type_boolean,
json_type_double,
json_type_int,
@@ -92,6 +93,7 @@
* Get the type of the json_object
* @param obj the json_object instance
* @returns type being one of:
+ json_type_null (i.e. obj == NULL),
json_type_boolean,
json_type_double,
json_type_int,