Add a comment.
Reimplement page switching effect.
Rename `data-api3-path` attribute to `data-api-path`.
Drop `|| 'Unknown'` constant in the admin breadcrumbs block.
Refactor `event_actions`.
Add support of Wire handlers without arguments.

Also fix check of handler arguments.
Style changes in the floatbar handler.
Expose `NodecaLoader` on `N.loader`.
Style changes on client files. Drop /*global*/ declarations.
Complete reorganization of `common` package.
Improve IO events.

- Add `io.success` event.
- Pass reply data to event handlers.
Complete client script of `debug_timeline` block.
Sync admin client files.