UJOC-6: Additional out-parameter "is_null_type" for function "ujo_element_get_type"
- add wanted parameter to function "ujo_element_get_type"
- adapt test helper functions to changed function "ujo_element_get_type"
- add missing element types to helper functions
- adapt existing tests to changed function "ujo_element_get_type"
Edited by Björn Latte