What's new in at-spi2-core 2.51.90:

    Add an attribute-changed signal in atk, and update libatspi attribute cache.

* Add GetTextSelection and SetTextSelection to Document interface.

* Add atspi_device_generate_mouse_event, and implement for mutter.

* Have atspi_device_add_key_grab return 0 if XIGrabKeycode fails.

* xml: Add Embedded to the Socket interface

* Don't return uninitialized values if atspi_component_get_size/position fail.