What's new in at-spi2-core 2.48.4:

* Add atspi_get_version() to return the runtime version of the AT-SPI library.

* collection: Fix match testing for attributes.

* collection: Avoid locking up if an object has a very large child count

* Fix possible NULL pointer dereference when deregistering an event listener.

* Various fixes for the new key grabbing API.