Multiple npcs can attack in single combat

[GregHib]

Due to "under_attack":

if (character.target == null || !Target.attackable(character, target)) {
   character.mode = EmptyMode
   return
}

npcCombatStop { target ->
    if (target.dead) {
        set("face_entity", target)
    } else {
        clearWatch()
    }
    target.stop("under_attack")
    target.attackers.remove(this)
    this.target = null
}

!attackable resets combat which removes the targets "under_attack" allowing the npc to attack, they take it in turns hitting and then the previous resets the under_attack flag allowing the next to attack.

Could really do with tidying up starting combat