Road Atlanta (depreciated) 2.0

I fixed the terrain properties which were all messed up. Mostly had to reassign terrains and rename a few. Also cleaned up under the road where there was some dirt making the road dusty, with the new terrain materials fixed.

Fixed a few props which looked bad and misplaced. Fixed a few holes in the concrete barriers. By request, I removed the barriers from the short and club course, so you can tool around on some alternate layouts; they may not be super smooth, mind you.