hasAlternatingParity

  Write a static method called hasAlternatingParity that
   returns whether or not an array of integers has alternating parity (true if
   it does, false otherwise).  The parity of an integer is 0 for even numbers
   and 1 for odd numbers.  To have alternating parity, a list would have to
   alternate between even and odd numbers, as in the following list:

        [3, 2, 19, 8, 43, 64, 1, 0, 3]

   If these values are stored in an array called data and we make this call:

        hasAlternatingParity(data)

   the method would return true.  If the array instead stored these values:

        [2, 13, 4, 1, 0, 9, 2, 7, 4, 12, 3, 2]

   it would return false because there are two even numbers in a row (4, 12).

   By definition, an empty list or a list of one element has alternating
   parity.  You may assume the values in the array are not negative.