[r6949] stacked elevated ways can be deleted from the bottom; slopes

[whoami]

Pak128.Britain (here: r1338) has some nice elevated roads.
These can be stacked, and it is properly checked whether any new stretch has a foundation.
But once a piece has been built, the elevated ways below it can be deleted.
Also, slope tools can be used quite freely under elevated ways, which also looks incorrect

[asaphxiix]

this is normal behaviour

[ӔO]

I guess, ideally, the game will draw some legs in the open areas under the elevated way, but I think that would require quite a few additional images on all the possible terrain underneath.

[kierongreen]

Yes at some point elevated ways and bridges need to be rolled together, along with images for different terrain underneath. The number of images that'd be required would be quite large though at AEO says...