[svn 3274] Items don't regenerate but still decay

[complexityQuantifier]

Maybe this was a design decision, but it seems like now that items and NPCs don't regenerate on re-entering a level, items shouldn't decay?

It would maybe be okay if they decayed less often? Like 1/10 chance for each item each time you reenter the level? Or with a half-life of 20,000 turns, checked when you re-enter the level? (That's probability (1/2)^(t/20000), where t is the number of turns since you last were on the level. And I have no idea whether 20,000 is the "right" number.)