Refactor Game Score Functions

[nery-lara]

There is a lot of duplicate code for keeping track of the high score and score of the game. These functions are found in the classes for every level. Factor them out so that they are only declared once in the entire project and have the methods just be called when needed.

[joelbagan]

Renaming to "Refactor Game Score Functions"

Consider creating a helper class which each level/difficulty has an instance of, which handles the score.

F17 OK 100pts