utils: Make the activation/panel client fetching more flexible
utils: Make the activation/panel client fetching more flexible

We now look for the actor to activate / to get get panel client from by
walking the scene graph until we find the actor whose parent is the stage. We
then get the panel client from that / fired the activated signal on it.

meego-netbook-ux/meego-panel-myzone,meego-netbook-ux/meego-panel-myzone,kkszysiu/gnomesocial,kkszysiu/gnomesocial