Rename all occurrences of 'level' to 'stage'
Create Level class
Refactor the Player class to reference the current level's goals property
Keep track of visited goals and reset the player's position after a successful visit
Refactor Player class

-Add reference to the props array
-Create die method to avoid repetition in the main game loop
-Create a new prop upon reaching a goal
Flipped water collision logic

-waterCollision is now true when colliding with water and not a floating obstacle