Documented the new way of listening to events as well the new
events that could be listened thanks to the recent refactor.
Also uses the versionadded directive to document when something new
is added to the library.
Change the description of on_error to reflect that exceptions are logged
and not output by default. Add a note about not configuring logging
causing exceptions to be silently ignored in handlers in the API. And
add some more explanations and a simpler configuration example to the
logging description.