fix empty MarketItem infos

After getting the MarketItem of a PurchaseWithMarket
PurchasableVirtualItem.
When trying to get this MarketItem's market data (marketPrice,
marketDescription and marketTitle) we get empty data.
The problem was that we weren't passing the right data from jni to the
MarketItem's constructor.
Merge pull request #275 from geonak/master

fix empty MarketItem infos