* Revised payment request handling to use genesis block hash instead of network name, enabling
support for more networks that just Bitcoin main and test net.
* Disable payment protocol certificate unit tests; we don't modify this code, and regenerating the test data is likely to be significantly time consuming. Will re-enable once discussion on spec is concluded.
Add support for a Payment Protocol to Bitcoin-Qt.
Payment messages are protocol-buffer encoded and communicated over
http(s), so this adds a dependency on the Google protocol buffer
library, and requires Qt with OpenSSL support.
