Reset Item definition, removed all non-essential fields.
Framed Item object.
Added Category type and pickler.
Added Country and pickler.
Added Currency and pickler.
Renamed Buyer to Payment; added pickler for ListingTypeCode.
Added PaymentMethod and pickler.
Added PicutreDetails and pickler.
Added ReturnPolicy and pickler.
Added ShippingDetails, ShippingTypeCode and ShippingServiceOptions with picklers.
Added xpSiteId and Maybe'd Item.
Added Item and ItemId pickler.
Added new modules to cabal file.
Merge branch 'minimum-item'

* minimum-item:
  Added new modules to cabal file.
  Added Item and ItemId pickler.
  Added xpSiteId and Maybe'd Item.
  Added ShippingDetails, ShippingTypeCode and ShippingServiceOptions with picklers.
  Added ReturnPolicy and pickler.
  Added PicutreDetails and pickler.
  Added PaymentMethod and pickler.
  Renamed Buyer to Payment; added pickler for ListingTypeCode.
  Added Currency and pickler.
  Added Country and pickler.
  Added Category type and pickler.
  Framed Item object.
  Reset Item definition, removed all non-essential fields.