Added highscore table
Added highscore

Highscores are loaded from local storage when the app begins, saved to local storage after each level and updated everytime you get a new score.
HighscoreList can now be saved and loaded from local storage
Coins now render inside the building hitbox
Highscore can now be saved to local storage.
Merge branch 'master' of https://github.com/kpro-gr10/Power-Supply