"item,activated" smart callback is added to notice when an item is
activated.
"item,activated" smart callback is called as follows.
1. Item push is finished and the new item is activated.
2. Item pop is finished and the previous item is activated.
void *event_info in smart callback is the activated item pointer.
"push,finished" and "pop,finished" smart callbacks are added to notice
when push and pop operation is finished.
New smart callback signals are added as follows.
"push,finished,item,activated" : Called when item push is finished and
void *event_info in smart callback is activated item (new item).
"push,finished,item,deactivated" : Called when item push is finished and
void *event_info in smart callback is deactivated item (current item).
"pop,finished,item,activated" : Called when item pop is finished and
void *event_info in smart callback is activated item (previous item).
"pop,finished,item,deactivated" : Called when item pop is finished and
void *event_info in smart callback is deactivated item (current item).