[crossfire] Arch category... wall dressing?

[Mark Wedel]

  The fact that they may be usable without walls (and as floors) suggests that 
maybe arch/wall isn't the best place.

  I'm not sure why things like the roadways are in the wall directory and not 
floor directory.  It is probably because those used auto join functionality like 
the walls (to make laying them out easier), and not that it was necessarily the 
right place for it.

  I'd also say that depending on number of objects, further refinement of just a 
overlay directory may be desirable - for example, could have:

arch/overlay/plumbing
arch/overlay/carpets
arch/overlay/...

  I'd tend to suggest a top level directory as last I looked, the editor grouped 
things by top level directory name, and I'd think it may be more useful to 
find/use them if one didn't have to look in wall.  And from a place expecting to 
find those things, wall might not be the intuitive place to look.