Unfortunately, BitWallet is not the app that is rebroadcasting the transaction. BitWallet only broadcasts the transaction once (according to the BitWallet developers). It is other nodes on the Bitcoin network that are continually rebroadcasting the transaction.
Then they will eventually drop it, a lot of nodes already have. You will need to import the keys into a new wallet so you can create a "double spend" which pays the minimum fee.
Thanks. I imported the keys into MultiBit, but MultiBit wouldn't let me do the "double spend" because MultiBit ALSO sees the transaction as still pending/unconfirmed. Perhaps MultiBit is pulling its information from the Blockchain.info site?