d1d483491f Make `hex` in `internals` optional (Martin Habovstiak)
Pull request description:
The `hex` crate is not always desirable - e.g. when the consumer wants to work with raw data only. We already had this optional in `hashes` but if `hashes` is going to depend on `internals` it would break this property.
This change makes `hash` optional, since it's easy: there's just one struct that depends on it.
ACKs for top commit:
tcharding:
ACK d1d483491f
apoelstra:
ACK d1d483491f5f0181e60778e557fadd99b44b5d30; successfully ran local tests; nice
Tree-SHA512: c20091e6febb49b9114273c280580ddcdafc91893f3c73288b374f51990f09f035a044806dd26777148f2e4341ad082ab05f1b49f8ceb3bcd24eb210ffa5fd5f