TODO

 - Add functionality so that there is a master clue
   and each jumbled word will contain one or more letters
   that will make up the master clue.
 - Allow user to select number of letters per word.
 - Allow user to select number of master clue letters per word.
 - Add ability to jumble single words.
 - Improve documentation.
 - Move dictionary read to separate method.
 - Add cgi script to examples.