Fix various potential null ptr deref and int32 overflows

This fix errors that can happen when ingesting very large JSON files
when hitting the maximum heap size of the process.

json_object.c

@@ -934,6 +934,11 @@ struct json_object* json_object_new_array(void)
 	jso->_delete = &json_object_array_delete;
 	jso->_to_json_string = &json_object_array_to_json_string;
 	jso->o.c_array = array_list_new(&json_object_array_entry_free);
+        if(jso->o.c_array == NULL)
+	{
+	    free(jso);
+	    return NULL;
+	}
 	return jso;
 }