* Update item_airbox.cpp
Also reset the velocity on Touch, just to avoid the "invisible" entity to keep moving.
Let the reset on "Restart" too in case of, despite facultative.
Final version: Reset all the axes of the velocity to make the sure the item spawns with a complete null velocity (I did not do that before more in order to take in consideration the possible custom X/Y speed we could give to them, like via plugin, but I finally decided to clean up all, the plugins could still affect it later if needed).
