powerup_override

Powerup override occurs when player under an old powerup consumes additional powerup.
The situation can be resolved as:
1.Both powerups are active if compatible.
2.Old powerup stays. The new powerup is ignored.
3.Old powerup is replaced by new powerup. This is most common solution.
4.Powerup override: Old powerup is only replaced if its lower in rank than new powerup.(i.e. the stronger powerup applies).