Prevent livelock and deadlock at startup.

Also fix some clippy lint warnings etc.

Release 1.0.4

Primarily dependency bumps + clippy fixes

Use top level version numbers

Keep things up to date.

 * Bump dependencies, and deal with the fallout from all of that, sigh.
 * clippy has found new things to complain about, so fix them too.
 * bump copyright years while we are here.

and so on.

Bump dependencies based on dependabot suggestions

Bump to 1.x.x

Fix problem with missing os-poll feature from mio

Update .lock file

Improve socket listening behaviour.

- Add `default-listen-style` configuration option to change the default
  DNS listen style.
- Remove dhcp-listeners, as the feature could never possibly work.
- Some better error reporting of listen failures.

Bump to -rc3