Replace game control links in game play page

Replace with buttons that have icons
Add topRowHeight variable to sass assets

Vertical align puzzle text
Add notifications to GameController

Remove errors from GameController (replaced by notifications)
Remove win/lose todo's (solved by notifications)
Fix guess method, solve method in Hangman

Add notifications to Hangman
Store notifications to Session
Remove errors from Hangman
Add game notifications partial

Remove game errors partial
Include game notifications partial in game play page
Clean game play page (remove debugging information - keep solution)