e3b059cebf Implement Display for block::Header (Tobin C. Harding)
Pull request description:
Not all the fields within `block::Header` implement `Display` however a block header can reasonably be displayed by using 160 hex characters.
Implement `Display` for `block::Header` by printing the header in hex in the same layout as we hash it in `block_hash`.
Close: #3658
ACKs for top commit:
apoelstra:
ACK e3b059cebfb917c3a876cc5a39d942d2dead475c; successfully ran local tests
Tree-SHA512: c1ff0d73562c9e00e93659f385a471c2d7912e1f09faf6c646bd7864d1a98e6e2baddebfcd1a032bf5adc3e27586022927261c8867098f7e7bf166bf35a9ffbd