- Using `@action` annotation to indicate methods that are allowed to be
executed as actions
- The output and errors of an action are automatically wrapped into a
`Response` object without any response build required on the plugin side
- More consistent naming for many methods, plus added a more extensive doc.
- Refactored the entry points for the daemon and the pusher into two
classes, easier to encapsulate and wrap into tests.
- Removed the local backend - managing the concurrency of two processes
reading and writing on the same socket at the same time was too much,
and its utility outside of the tests (which can have mock backends as
well) is quite modest.
- Managing stop events on the bus. Still some work to do tho.
- Fixed several bugs.
