112.06.00

- Added `Writer.behave_nicely_in_pipeline`, which makes a program behave
  nicely when used in a shell pipeline where the consumer goes away.
- Modernized code style.
- Removed spurious overrides in `Signal`: `set` and `signal`.

    These overrides are no longer necessary because the functions moved
    from `Core.Signal` to `Core.Signal.Expert`.

- Moved `async_extra`'s `Udp.bind_to_interface_exn` to `Unix`.