The article I read indicated that an election that started as a two person contest that ends because of the death of one would leave the “contest” null and void.
Could be ... that’s not my understanding.
In any event, the term of office of The Won ends at noon, Jan 20, 2017.
If no incoming president has been chosen, the Speaker of the House becomes president.
If Barky O tries to stay in office past that time, THEN we have a constitutional crisis and it’s time to invoke the Ceausescu Protocol.
Here’s one discussion of the topic: