[orca-list] Bonobo is now an optional dependency

[Joanmarie Diggs <joanmarie diggs gmail com>]

Hey all.

Because bonobo is deprecated, it cannot continue to be a required
dependency of Orca. But because we have -- and will continue to have --
users of older versions of GNOME running the latest version of Orca, we
can't just rip it out completely. As of a few minutes ago, bonobo became
an optional dependency.

You shouldn't notice any differences as a result of this change. And if
you do, I'd really, really like to know about them soon. Thus, once
again, your testing love would be very much appreciated.

Thanks guys!
--joanie