zindex (zorder) to paint the shapes in order
Merge branch 'master' of https://github.com/lorencr7/shokoban

Conflicts:
	Shokoban/src/model/GameController.java
	Shokoban/src/sd/emse/shokoban/Box.java
	Shokoban/src/sd/emse/shokoban/Player.java
	Shokoban/src/sd/emse/shokoban/Shape.java
	Shokoban/src/sd/emse/shokoban/Square.java
	Shokoban/src/sd/emse/shokoban/Storage.java
	Shokoban/src/sd/emse/shokoban/Wall.java