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.
Change how the old style on_error event is called to match the new style
on_error event. Both are now called in case an exception is raised in
an user defined event handler, and will by default print the arguments
of the event tha raised the exception and the traceback for the
exception. In addition, overridding the on_error handler supresses this
behaviour.
Rapptz
Hornwitser