- Also rearrange some code.
- Drop unused dependencies.
- Fix examples.
- Fix error handling.

- Generate from macro.
- Add missing fields.
- Make iterator work with new `Kind`.

- Add `impl_enum` macro.
- Tidy up documentation and naming of fields.

- Use `bitflags` crate where it makes sense.
- Move more complex fields into their own modules.
- Use macros to automatically generate basic fields.

Resolves #5