* add cancels to HOOK_BEFORE_PHYS_STEP allowing for custom step systems
* give lua mods access to stepArg and nextPos from hanging and air step; fix a crash when m.floor is null
Player life counters are separate.
When one player dies they lose a life and are turned into a bubble.
If the other player pops it, they are alive again.
If all players are bubbled, they get kicked out of the level.
If the bubbled player ran out of lives, they can not come back to life
until the level is over.
Whenever a level change happens, everyone's life count is set to a
minimum of two.
No game overs.
Took heavy inspiration from Kaze Emanuar