[Therion] plan cross-section

seems that cross-section scrap must have a projection `none', which means that therion cannot use stations to scale it "properly". i had to draw a vertical cave, a sequence of pits, one on top of the next. instead of drawing a plan, with plenty of maps shifted to the side, i preferred to draw plan cross-sections nearby the shafts as cross-sections (with a section line marking their position on the pit). i would also like to have one north symbol on the map, to mark the orientation of all the plan cross-sections. i did it fiddling with the sources, but a "more stable" solution is appreciated. thanks for the help, marco