Python Classwork: Sentence Stats
    Write a Python program named "SentenceStats.py" that has the user
    enter a sentence (with a "sentence" considered to be any combination
    of one or more words).

    Then report to the user the following information:
      1) How many words are in the sentence
      2) How many vowels are in the sentence
      3) How many consonants are in the sentence
      4) How many non-letter characters (numbers, spaces, punctuation)
         are in the sentence
      5) How many uppercase letters are in the sentence
      6) How many lowercase letters are in the sentence
      7) The shortest word in the sentence
      8) The longest word in the sentence

    When determining #1, #7, and #8 above, consider a word to be any
    combination of characters that has a space on either or both sides.
    The one exception is if the user enters only one word (no spaces).

    For #7 and #8 above, if there are multiple shortest/longest words
    of the same length, display all of them.

    Unlike your previous Python assignments, you must use a separate
    function to get your user input, as well as separate functions for
    each of the eight tasks above.  The "main" area of your program
    should consist almost exclusively of variable declarations and
    calls to the individual functions.

    As always, all of your code must be your own, written entirely by
    you.  You may not import or use any external functions.  You may,
    however, use global variables in your program.  Your program's
    output should be neat, organized, and easy to read/understand.