* Add a character to this word. If this is a whitespace character
* adding to a non-whitespace word, create a new word and return that;
* similarly if this a non-whitespace character adding to a whitespace
* Add a character to this word. If this is a whitespace character
* adding to a non-whitespace word, create a new word and return that;
* similarly if this a non-whitespace character adding to a whitespace
*
* @param ch the new character to add
* @return either this word (if it was added), or a new word that
*
* @param ch the new character to add
* @return either this word (if it was added), or a new word that