Advanced items in market oddity

[jt-traub]

It is pretty hokey that advanced items will only show up in markets IF you have have of that item in the region. (this is what the global MARKETS_SHOW_ADVANCED = 0 does, and that's the setting for all games)

I can totally see not showing advanced items all the time. IE, if you have never heard of mithril or seen it, then you wouldn't know to check for people buying (or selling it).. But.. once your faction has discovered it, you should totally have the ability to see it.

I will probably tweak this at some point to allow that type of configuration.