pass test select_elements_starting_with_a
pass test remove_nils_from_array
pass test remove_nils_and_false_from_array
pass test reverse_every_element_in_array
pass test every_possible_pairing_of_students
pass test all_elements_except_first_3
pass test add_element_to_beginning_of_array
pass test array_sort_by_last_letter_of_word
pass test select_elements_starting_with_vowel
pass test get_first_half_of_string
pass test make_numbers_negative
pass test separate_array_into_even_and_odd_numbers
pass test number_of_elements_that_are_palindromes
pass test shortest_word_in_array
pass test longest_word_in_array
pass test average_of_array. Refactored test get_first_half_of_string
pass test add_together_keys_and_values
pass tests remove_capital_letters_from_string, round_up_number, round_down_number
pass tests format_date_nicely
pass tests format_date_nicely