-working update() with EntitiesData structure input

-added support for 'const' components input (read only, future usage)

source/ecs/entity.d

@@ -17,7 +17,7 @@ struct Entity
         EntityManager.instance.id_manager.update(this);
     }
 
-    T* getComponent(T)()
+    T* getComponent(T)() const
     {
         EntityManager.EntitiesBlock* block = gEM.getMetaData(&this);
         EntityManager.EntityInfo* info = block.type_info;