706a135de6 bitcoin: Add an example of doing I/O to encode/decode (Tobin C. Harding)
Pull request description:
In an effort to improve the documentation on `bitcoin_io` add an example in `bitcoin` crate that demonstrates a few things:
- Encode/Decode a `rust-bitcoin` type to/from a stdlib type.
- Encode to a custom type by implementing `bitcoin_io` traits.
- Encode to a foreign custom type by using the `bitcoin_io::bridge::FromStd` wrapper.
Later we can link to this example online in the `bitcoin_io` docs.
ACKs for top commit:
apoelstra:
ACK 706a135de6ca2be0231c2f62f4f2b156e08c9a49; successfully ran local tests
Tree-SHA512: cd3ff4067d5b86031255cb31fe17dea3fd22479699d32efad93c359de465ef6250f29aa4c43ce4218ae623fa6c355661960c11908a729a895655319141b82852