title: NSSortDescriptor for comparing CLLocation objects in Cocoa/iPhone
body: <p>I have an array of CLLocation objects and I'd like to be able to compare them to get distance from a starting CLLocation object. The math is straight forward but I'm curious if there is a convenience sort descriptor to go about doing this? Should I avoid NSSortDescriptor and write a custom compare method + bubble sort? I'm usually comparing at most 20 objects, so it doesn't need to be super efficient.</p>