Add a button to show letters as uppercase or lowercase
Fix sort by size the word list

This is needed later to avoid put words inside other words
Add a option to avoid full ooverlap of words in the grid
Fix setting the class in the wordlist when a word is selected

How we can show the word uppercase or lowercase,
but the class name need be always the same.
Store the word positions to use intead of solved positions

The routine used to solve the game and get the word positions
can't manage avoid words inside other words. We store the positions
were the words are placed to do the verification when the user play.
Add a alert to notify the user when words have less than 3 chars