per-display bonobo-activation registration

[Mark McLoughlin <mark skynet ie>]

Hey,
	I'm just looking at #69650 and I thought I'd poke for comments
..

	The problem is, we register a PanelShell on panel startup with
oaf. If there is already one registered we exit out. But what if you
want have two different sessions on two different displays?

	How are you supposed to use bonobno-activation in this case?

CHeers,
Mark.