Add reactive option to on_pre_player_died

[mheguy]

Haven't looked through the code much, but from what I understand it's running every tick? Maybe consider something that triggers on_pre_player_died instead to lower the impact of your mod?

[muppet9010]

When I started this I didn't realise that you could override players health on the death event to avoid death. I'll add it as an option between preemptive jumping and death avoidance jumping.

[muppet9010]

done in 0.1.1 under 5f25d9e