6acf9ac8b8 Patch hashes and update the code (Martin Habovstiak)
Pull request description:
This patches `bitcoin_hashes` to use the version in the repository and fixes the code after removal of `Deref`.
ACKs for top commit:
tcharding:
ACK 6acf9ac8b8
apoelstra:
ACK 6acf9ac8b8
Tree-SHA512: b779fa79309f1d648020146b58e96346b67e9f76e29551cbd50251ea6bb7bcfc4c5d42f49cc7ad5660dcd0a5f6306efe96dfcd9530e4b32c62edf4af7076d830