Add documentation comments to various lua engine classes

game/engines/default/engine/Actor.lua

game/engines/default/engine/ActorsSeenDisplay.lua

game/engines/default/engine/Astar.lua

game/engines/default/engine/Autolevel.lua

game/engines/default/engine/BSP.lua

game/engines/default/engine/Birther.lua

game/engines/default/engine/Calendar.lua

game/engines/default/engine/CharacterBallSave.lua

game/engines/default/engine/CharacterVaultSave.lua

game/engines/default/engine/Chat.lua

game/engines/default/engine/DamageType.lua

game/engines/default/engine/DebugConsole.lua

game/engines/default/engine/Dialog.lua

game/engines/default/engine/DirectPath.lua

game/engines/default/engine/Emote.lua

game/engines/default/engine/Entity.lua

game/engines/default/engine/Faction.lua

game/engines/default/engine/FlyingText.lua

game/engines/default/engine/FontPackage.lua

game/engines/default/engine/Game.lua