box-layout: store the 'from' actor when focus moves out of the widget
box-layout: store the 'from' actor when focus moves out of the widget

Store the 'from' actor when focus moves out of the widget so that it can be
used for the 'prior' focus hint when focus is returned to the widget.

pwithnall/mx,pwithnall/mx,clutter-project/mx,jonnylamb/mx,jonnylamb/mx,jonnylamb/mx,clutter-project/mx,jonnylamb/mx,clutter-project/mx,pwithnall/mx,pwithnall/mx,clutter-project/mx