Wev

Fixed publish to GitHub.

1. Include the `wev-echo` plugin.
2. Stop logging "Starting..."
3. Allow `wev.yml` and `wev.user.yml` as configuration files.

- Add `ResolutionSupport` types and documentation.

- Added `version` property to `PluginBase`.
- Log each plugin's version as it is loaded.

- Removed pre-release note.
- Added `example.wev.yml`.
- Handle plugins raising `CannotResolveError`.
- Reduced logging of confidential information.

- Handle `CannotResolveError`.