The GDBus bindings in gjs have been updated to leverage metaclasses
and gobject inheritance, which should result in cleaner and more
maintainable code.
Logind provides a Suspend method, which we should use instead of
the UPower API when available. Expose this in loginManager, using
the UPower API for the ConsoleKit implementation.
https://bugzilla.gnome.org/show_bug.cgi?id=686482
Various code around had different paths for ConsoleKit and
logind. Consolidate it by making an abstract class that all
callers can use, which hides the implementation details of the
two daemons.
https://bugzilla.gnome.org/show_bug.cgi?id=682096
