daemon: Use Atspi's main loop instead of GLib's
daemon: Use Atspi's main loop instead of GLib's

To enable D-Bus property caching in libatspi, the client must call
atspi_event_main.

https://bugzilla.gnome.org/show_bug.cgi?id=743267

GNOME/caribou,GNOME/caribou,GNOME/caribou