altered bubblesort algorithm to sort from lowest to highest keys instead of highest to lowest
added compare function to SortList

- no longer need to compare specific SortElements
- metric still works as intended
- no longer need SortElements ( can switch back to bare BigInteger)
added another compare function to SortList

- compare element of list to another BigInteger
- needed by mergesort
using SortList new compare function in all Sorters