Word Thing
Create a non-static class named 'WordThing' in its own file.  The class should
contain a single constructor that takes a single string as its argument.  The
constructor should store the value of the submitted string in an internal
class variable (which, along with any other internal variables in the class,
should be private).  You may assume that the submitted string will contain
only uppercase and/or lowercase letters (no spaces, numbers, punctuation,
etc.).  The method 'main' and the keyword 'static' must not appear anywhere in
the 'WordThing' class.  The class should contain the following public methods:

    displayWord
       Arguments:  None
       Displays:   The "active" word (by itself, on its own line)
       Returns:    Nothing
    -------------
    countLetters
       Arguments:  None
       Displays:   Nothing
       Returns:    An integer equal to the number of characters in the "active"
                   word
    -------------
    reverseWord
       Arguments:  None
       Displays:   Nothing
       Returns:    A string containing the characters in the "active" word in
                   reverse order (you must use a 'for' loop)
    -------------
    changeWord
       Arguments:  A single string
       Actions:    Changes the "active" word to the new input
       Displays:   Nothing
       Returns:    Nothing


Advanced Option #1
To the 'WordThing' class, add another public method named 'alphabetize'
that returns a string containing the letters in the "active" word in
alphabetical order (ignoring case).

Advanced Option #2
To the 'WordThing' class, add another public method named 'variations' that
returns an ArrayList of strings of all of the different permutations of the
letters in the "active" word.  So, for example, if the word is "cat", then
your method should return an ArrayList consisting of these six strings:
"cat", "cta", "act", "atc", "tac", and "tca".  If a word contains more than
one of the same letter (e.g., "animal", "cook", "situation"), make sure
your returned ArrayList does not contain any duplicate entries.  So, for
example, for the word "too", your method should return an ArrayList that
has only three words in it:  "too", "oot", and "oto".