962abcc963 Add serde regression tests (Tobin Harding)
Pull request description:
Attempts to add regression tests for _all_ types defined in `rust-bitcoin` that implement `Serialize`/`Deserialize`.
- Add a `tests` directory and implement regression tests in there
- Use files for input hex and output bincode to reduce source file clutter
- Copy test block and `include_bytes!` usage from RCasatta's [PR](https://github.com/rust-bitcoin/rust-bitcoin/pull/750)
- Uses Kixunil's macro suggested below
- Adds a single regression test to `util/taproot.rs` for private types
## Note to reviewers
- Uses JSON for opcodes in a separate file (`tests/regression_opcodes.rs`), for all other tests uses bincode.
- Bypasses the order issue for maps by only serializing maps with a single element - is this correct?
Fixes#723
ACKs for top commit:
apoelstra:
ACK 962abcc963
sanket1729:
ACK 962abcc963. This has been open for a long time. Merging this in the interest of progress.
Tree-SHA512: e34e48e1c56fab5898bc74e7fb867435ed387d828dd3daf0c7d6df8f305e1da6883e91487115ac428618eb7d95bd16aa2cd209ca219684959bc95587ef0b4083
df57a195c1