Sound fixes

* Fixes volume being reduced to zero when pressure is above 100 kPa.
* Fixes volume not actually being reduced when the hearer is in low pressure.
* Fixes possible (not sure) runtime when the hearer of a sound is in space.
* Fixes sounds being hearable in space when source and hearer are separated by one tile.
* Fixes sound volume being reduced when the source is in view range.
* Fixes the effect of low pressure on sound being handled twice.

I don't want to get on anyone's case, but that PR should not have been merged the way it was.