modification resulting in the one shot of every zombie

modified:   src/game/GameLoop.java
adding the energy item

new file:   assets/textures/energy.png
new file:   src/item/Energy.java
modified:   src/rendering/TextureManager.java
Merge branch 'master' into energy
adding energy in the EnergyRoom

modified:   src/environment/room/EnergyRoom.java