Default implementations for some some functions atk_object_real_get_name,
* atk/atkobject.[c|h]
Move some implementation from GAIL:
Default implementations for some some functions
atk_object_real_get_name, atk_object_real_set_name,
atk_object_real_get_description, atk_object_real_set_description,
atk_object_real_get_parent, atk_object_real_set_parent,
atk_object_real_get_role,
atk_object_real_connect_property_change_handler,
atk_object_real_remove_property_change_handler,
atk_object_notify,
definition of property-changed signal.
Initialize pointers to NULL in atk_object_init().
Initialize uninitialized function pointers to NULL in
atk_object_class_init().