Added SimpleTerrain
Merge branch 'master' of https://github.com/antoine1023/WhatCouldGoWrong

Conflicts:
	src/wcgw/core/Entity.java
	src/wcgw/core/Game.java
	src/wcgw/core/Terrain.java
	src/wcgw/core/Vector2.java
	src/wcgw/view/GameJPanel.java
	src/wcgw/view/PlayerView.java