Massive reshuffling of headers

Mostly to clean up the defines and such, internalize scripts that don't
need to be called from ACS, and etc.
Fix broken health bars, extern AddCompoundScript

The health bars were broken by the wrong use of SetActivatorToTarget; we
only need to jump to the enemy for a brief moment to get their stats,
then immediately go back to the player. Don't jump twice.

I forgot AddCompoundScript when fixing the externs.