code: private static void sortheap(Quicksortable q, int size) {
          for (int i = size-1; i >= 1; i--) {
              q.swap(0, i);
              heapifyDown(q, 0, i);
          }
      }
docs: sorts the heap stored in q
  
  @param q The quicksortable to heapsort.
  @param size The size of the quicksortable.