Merge

1. Using the pseudocode in Section 5.5, write the method called merge. Be sure to test it before trying to use it as part of a mergeSort.
2. Write the simple version of mergeSort, the one that divides the deck in half and then uses sortDeck to sort the two halves. Then it uses merge to create a new, fully-sorted deck.

   Remember that sortDeck is a modifier and mergeSort is a function, which means that they get invoked differently:

     sortDeck (deck);              // modifies existing deck
     deck = mergeSort (deck);      // replaces old deck with new

3. Write the fully recursive version of mergeSort.