Add A_ClientsideACSExecute.
Fix RGF_MISSILES not giving to missiles unless they had NOBLOCKMAP removed.
Added event GAMEEVENT_LEVEL_INIT, which executes early in map initialization, before things are spawned, OPEN scripts executed, etc.
Rename GAMEEVENT_ACTOR_ARMORDAMAGED to GAMEEVENT_ACTOR_DAMAGED_PREMOD to more descriptively match its behaviour (as armor hasn't actually been damaged yet).
Move GAMEMODE_HandleDamageEvent calls up so they can fire for enemies/objects without an inventory.
- Renamed the weapon view pitch styles to better match actual behaviour.
Fixed jittery model interpolation, partly based on dpJudas's fix for GZDoom.
Added KILL Script type and associated flags and GameInfo keyword.