* xfce4-session/Makefile.am: Add xfsm-error.* and D-Bus stuff to the
      build.
    * xfce4-session/{xfsm-manager-dbus.xml,xfsm-client-dbus.xml}: Add
      D-Bus interface introspection files.
    * xfce4-session/shutdown.*: Make the shutdown type a real enum,
      and add values for 'ask', 'suspend', and 'hibernate'.
    * xfce4-session/xfsm-shutdown-helper.*: Make sure the shutdown
      types/commands don't clash with shutdown.h.
    * xfce4-session/xfsm-global.*: Add some GValue convenience
      functions.
    * xfce4-session/xfsm-error.*: Add XfsmError type, and register the
      error domain with D-Bus.
    * xfce4-session/{xfsm-manager.*,xfsm-client.*}: Implement D-Bus
      server for org.xfce.Session.Manager and org.xfce.Session.Client.
    * xfce4-session/main.c: Hook up some D-Bus stuff.
    * po/POTFILES.in: Add xfsm-manager.c and xfsm-client.c to POTFILES.

(Old svn revision: 28049)