xPosition in sprite and rest of classes that extend Sprite Refactoring

[UCSBWillHuang1997]

xPosition variable in Sprite.java was declared as protected so you cannot pass the variable to a class that extends Sprite.java (Runner.java, Snail.java, etc) and so you had to update the local xPosition in the class and the xPosition in the extended Sprite class.

[jalexanderqed]

To be clear, you should remove one of these versions of xPosition so that the information is not duplicated.

[jalexanderqed]

F16 OK (70 pts)