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.