a5f904559d primitives: Make hex optional (Tobin C. Harding)
Pull request description:
Make the `hex` dependency optional. This means not implementing
`Display` for some types if `hex` is not enabled and only implementing
`Debug`.
Also without `hex` enabled:
- We loose the ability to parse an `OutPoint` from string because we
can no longer parse `Txid`.
- We loose the hex formatting of witness elements.
Note also that `primitives` builds with the `serde` feature even if
`hex?/serde` is excluded from the `serde` feature. I found this
surprising.
Close: #4183
ACKs for top commit:
apoelstra:
ACK a5f904559d3b5d2dfbcbed8b1746305e32103fee; successfully ran local tests
Tree-SHA512: c105e089508036af8251cb923f3eda163b8f2d6151ea043aa1489edb6ce396975d1f598a240f4ca6e48f6ef780774f7d86cb70ec9399f3d2ff87c0ac53ceee91