I added setShuffling because I was asked on this list to enable a way  
for elements entered for the same timestep to be removed from the  
Schedule in a predictable order (that is, no shuffling of those  
elements).  However while the order is *predictable* it is by no means  
*expected* -- since the Schedule uses a binary heap underneath, it is  
*not* the case that elements will be stepped in the order in which  
they were inserted in the Schedule in the first place (though it is  
*sometimes* the case).  Because of the high possibility for  
misunderstanding, and the very low value (I think) in having the  
feature, I'm thinking of deleting setShuffling entirely and requiring  
that objects be shuffled.

Any opinions?