What's new in at-spi2-core 2.3.4:

* Add some dbus message signature checks.

* Fix a crash if a device listener incorrectly returns a non-bool.

* Fix for BGO#666870: Keystroke listeners do not work unless an event listener
 is also registered [also needs updated at-spi2-atk]

* Fix for BGO#667254: Some atspi-selection_* functions were broken.

* When a call times out, ping the connection and avoid making subsequent calls
 until the ping is answered.