[crossfire] Player-owner shop proof of concept

[Nicolas Weeger]

> But i'm afraid what happens when high lvl players sell quest items
> for very few platinums, and so soon many low level players maybe run
> around with those stuff... Or high level players sell stat potions
> very cheap so low level players have full stats very soon.

Well, right now you can simply give a weapon to a player, so it's not
that different :)
Also, don't forget there is the item level, which should prevent low
level players from using too powerful equipment.

Nicolas