Better water processing

[thedocruby]

Instead of just dampening sounds when under water, the mod should dampen sounds that are not in water when the player is, and vice-versa. Also, when in water, sounds that are also in water should have a special effect applied to make them sound realistically in water.
also sound dissipation with distance is less in water, and the "air absorption" should not apply in the water, instead a new water absorption setting should apply.