Persist last exchange rate, so we can show it quickly after an app restart
[DO NOT MERGE] Bitcoinj 0.11 flavor
[WIP] Update to bitcoinj 0.11-SNAPSHOT
Present dialog on insufficient funds when sending coins
Run wallet event listeners on bitcoinj network threads
Labs: Put BIP70 payment request on NFC tag and be prepared to read it
Labs: Put BIP70 payment request into QR-code and be prepared to read it
Labs: Use BIP70 PaymentMessage/PaymentACK messages in Bluetooth offline transaction protocol if payment was initiated by a PaymentRequest message