Use BPS based event dispatcher

Use BPS based event dispatcher

Create a QPA specific subclass of the blackberry event dispatcher
(basically the BPS equivalent to the QUnixEventDispatcherQPA created
by createUnixEventDispatcher()).

Create an event dispatcher event filter that will receive all BPS events
and then either handle them itself or delegate to event subtype
specific handlers.

Change-Id: I112e0274156727d3aa9e5693b59d041c65be4daf
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>