This was causing the following critical when running bloatpad twice:
GLib-CRITICAL **: g_hash_table_insert_internal: assertion `hash_table != NULL' failed
Have one simple _get() API that returns the group immediately, in an
empty state. The group is initialised on the first attempt to interact
with it.
Leave a secret 'back door' for GApplication to do a blocking
initialisation.
There are no public 'exporter' objects, so don't allude to them
in the function names. At the same time, we want to make it clear
that these functions are D-Bus specific.
The new APIs are
g_action_group_dbus_export_start
g_action_group_dbus_export_query
g_action_group_dbus_export_stop
g_menu_model_dbus_export_start
g_menu_model_dbus_export_query
g_menu_model_dbus_export_stop