Add a mix-in so we can save the DOM node in each bound instance
Add a mix-in so we can save the DOM node in each bound instance

pabigot/pyxb,jonfoster/pyxb1,jonfoster/pyxb-upstream-mirror,jonfoster/pyxb-upstream-mirror,jonfoster/pyxb2,CantemoInternal/pyxb,balanced/PyXB,jonfoster/pyxb2,pabigot/pyxb,jonfoster/pyxb1,balanced/PyXB,balanced/PyXB,jonfoster/pyxb2,CantemoInternal/pyxb,jonfoster/pyxb-upstream-mirror,CantemoInternal/pyxb