Documentation pass
Hidden Water.Think
Obsoleted Water.EnableShadows, EnableFog & EnableRefraction
Hidden GradientFogEntity.TickFrame, ParticleSystemEntity.OnMapCleanup, PrecipitationEntity.ClientTick
Implemented ParticleSystemEntity.SetControlPoint
Hidden SoundEventEntity.OnStartSound, OnStopSound
Made SoundEventEntity.StartSound, StopSound public
Added srcds genereated file to gitignore