[Done for V0.38] Allow invalid objects in editor

[Gambit37]

The editor won't allow you to place floor tiles on walls, so it's not possible, for example, to place teleporters on alcoves to support complex interactions.

Other invalid things that could be allowed for:

1) Wallitems on floor tiles (you might want to decorate an illusion wall for example)

I will update this list as a find any more...

Can you allow these items to be added but provide some kind of warning?

[Big-J-Q]

I'll second this one. Actually ie. the CSB-dungeon uses decorate items on movable walls, so it wouldn't really be an invalid situation. Don't remember if it's used in DM, but I'd imagine that a switch on a movable wall wouldn't be unheard of.

[Gambit37]

It works if you do it manually in the TXT file, just not in the editor.

[George Gilbert]

This can now be done in V0.38 editor (create the item in a valid place, then cut and paste it into the invalid position).