-Use Container class for answer buttons, inherit from Button
-Store fractions as decimals in JSON for now
-Move answer buttons so they don't overlap "demo" buttons
Merge branch 'master' of https://github.com/chrisknepper/xo-fractions-game
-Implement rudimentary grid system and display answer containers
Merge branch 'master' of https://github.com/chrisknepper/xo-fractions-game