Remove entity set case at null, no remove entity in the world.
Correct bug :

* Construction of ComponentMapper need by explicite, her.
* Position move in index and in Position Component
* postionVoid check if case content null value, no if is a active entity in world.
* Add debug fonction print Entity and position if position isn't void in index
Control Up, Down, Right, Left, is active but change the ned position in index, no visual effect.
Add clone functionality in EntityPosIndex.
EntityPosIndexSystem, now is singleton.
GameSystem is singleton.
Remove debug instruction, some serialisation, and use singleton modification.
UpdateLevelVisualSystem, read position index, and entity position.
For make animations.
Add UpdateLevelVisualSystem, in the world.
Merge branch 'master' into devel

Conflicts:
	game/src/main/java/org/geekygoblin/nedetlesmaki/game/Game.java
	game/src/main/java/org/geekygoblin/nedetlesmaki/game/systems/IngameInputSystem.java
Update the move of ned.
simplification main