Rename Words to Word

Remove notification methods in Hangman
Format default layout
Refactor guess method in Hangman
Refactor Hangman to use setCorrect and setIncorrect
Refactor solve method in Hangman
Refactor guess method Session notifications

Move Session notifications to respective reward and punish methods.
Add documentation to solve method for Hangman
Add documentation to punish method in Hangman
Update documentation for solve method in Hangman
Update documentation for Word
Add documentation for Word
Add addWord method to Word
Add deleteWord to Word
Move all Session statements to GameController

Refactor button name attribute to equal letter instead of letters in letter partial