Keeping HighScores

I just uploaded a newer version of the game. Now you have Highscores that remain even after you close the app. I also fixed a bug in which the reduced speed would stay the same even after you died and should have reset back to 15( the text said it's 15 but in reality it was still slower).

I'm planning on adding new features in the future including profiles with individual Highscores, and maybe add an option to change the color of the snake. 

I'll keep you updated.