-added more documentation

-remove update() function from entity
-currently max supported components count is 64 per type

source/ecs/system.d

@@ -18,6 +18,8 @@ import ecs.manager;
 *<br/>-void onDestroy();
 *<br/>-void onAddEntity(EntitesData);
 *<br/>-void onRemoveEntity(EntitiesData);
+*<br/>-void onChangeEntity(EntitiesData);
+*<br/>-void handleEvent(Entity*, Event);
 */
 struct System
 {
@@ -82,14 +84,14 @@ struct System
         return cast(const(char)[]) m_name;
     }
 
+package:
+
     struct EventCaller
     {
         ushort id;
         void* callback;
     }
 
-package:
-
     ///should system be executed in current update?
     bool m_execute = true;
     ///system id