Finished my engine reqs!

Totally done with saving/loading games and friction. Saver is a static
class to save/load and friction is implemented in Entity.
Merge branch 'master' of https://github.com/iebaker/game-final-project

Conflicts:
	bin/engine/World.class
	bin/game/GameWorld.class
	bin/game/Player.class
	src/engine/World.java
	src/engine/entity/Entity.java
	src/game/GameWorld.java