Adding it as an option in the actual program would be convenient.
Welcome to the forums Zoomie09.
There is a Shutdown option available, and has been for a long time. However it isn't inside the GUI though as per your suggestion, it's only available via a command line as seen here:
http://forum.pirifor...showtopic=16551
It does make absolute perfect sense though to have it in the GUI also as an option, so this is indeed a very good suggestion!!!