Add treasure pool information

[z16]

A function to get the current treasure pool as a table would be practical for LL-y features, among other things. It could get added separately, or by amending the get_items() struct.

[ReaperX]

In addition to this, I would also like to have an event that is triggered when an item falls from the treasure pool into inventory. I'm thinking of an addon that moves currency and forgotten items to sack or satchel while farming Dynamis. That would be very useful when there are only few free inventory spots.

[z16]

I'll open this as an additional issue, treasure pool information has been added now.