(svn r3996) -Fix: Slope and height information returned for some tile types is wrong

This leads to graphical glitches when drawing foundations.
This doesn't fix all problems, but at least some of them.

station_cmd.c

@@ -2032,7 +2032,7 @@ void StationPickerDrawSprite(int x, int y, RailType railtype, int image)
 
 static uint GetSlopeZ_Station(const TileInfo* ti)
 {
-	return (ti->tileh != 0) ? ti->z + 8 : ti->z;
+	return ti->z + (ti->tileh == 0 ? 0 : 8);
 }
 
 static uint GetSlopeTileh_Station(const TileInfo *ti)