add stop price text field
add Item class
pass Item in UserRequestListener
pass integration test makesUserRequestWhenJoinButtonClicked
pass Item to SniperLauncher and AuctionSniper
add unittest doesNotBidAndReportsLosingIfSubsequentPriceIsAboveStopPrice
add allowBid to Item
add losing to SniperSnapshot
pass unittest doesNotBidAndReportsLosingIfSubsequentPriceIsAboveStopPrice