runes and looking

[Tero Jyri Michael Pelander <tpeland@utu.fi>]

Crossfire 0.91.1

If you have some items _under_ a rune and the rune is invisible at the moment
you get "You see nothing there."  Also if you put items on top of a rune
(by create food spell for example) you only see the item you put there.
All the items under the rune are "invisible" at the same time as the rune is
invisible.  This means that if you have some floortype that has a name then
anyone can just click on the map to see if there is a rune.