fix/emitting-events-without-backpack-loaded

[Sadzurami]

Often we receive SO_Create messages before our backpack was loaded.

If we not handle that because of lack of backpack, we can miss important info. Same for SO_Destroy and SO_Update.

Also fixed item.position, now that represents correct position (previously we can get 1 or -1 position if item was acquired in past and we didn't update position for this item).