Sorting (Part 1): Binary Search, IsSorted, BubbleSort

At this point in the course, I like to do sorting before trees because it's good to talk about why "alphabetizing" data is a good thing to do. So we discuss binary search (closing out our assignment zero discussion of the guessing-game) and then introduce how to check whether a list is sorted, which naturally becomes BubbleSort when we try to fix out-of-order pairs.