[Therion] bad scrap overlay

[Martin Sluka]

Imagine two sloppy passages like faults side by side. On map, one of them 
should be drawn „above“ another one „bellow“. But there could be a 
problem for Therion - centerline in passage „above“ is on floor of it and 
centerline in passage „bellow“ is near ceiling. It means centerline of 
„bellow“ passage is higher than centerline of „above“ passage. So only 
human may decide what is „above“ and what is „bellow“.

m.s.