customizable can_explode condition

[patf0rd]

We have hp.can_explode to return true when the target's actual Health is lower than 40% of the source pet's MaxHealth.

Would like to see a customizable version being added, where we add a value for this Maximum Health (percent), i.E. 40 for Explode/Burst or 15 for Corpse Explosion (and whatever numbers new abilities might bring).