Function quicksort::quicksort_by

pub fn quicksort_by<T, F>(arr: &mut [T], compare: F) where
    F: Fn(&T, &T) -> Ordering, 

An in-place quicksort.

The algorithm is from Sedgewick and Bentley, "Quicksort is Optimal": http://www.cs.princeton.edu/~rs/talks/QuicksortIsOptimal.pdf