The star event will allow us to relay any custom events as well as
the ones used internally by Select2. This also makes it much
easier to start triggering events in general, as we don't need to
relay it in the core anymore.
A module has been created for the jQuery-facing events, and the
release announcement has been updated to mention the event name
changes.
This also adds some documentation about the public events.
`dropdownParent` controls the location of the dropdown when it is
automatically added to the DOM. By default, this is the body
element but it can be modified based on where the user needs it.
