using a better aproach to the lxml pickling problem: by setting _p_changed. Provided a helper class for XML and reverted r16557
using a better aproach to the lxml pickling problem: by setting _p_changed. Provided a helper class for XML and reverted r16557

re #5669
re #5707

ZeitOnline/zeit.cms,ZeitOnline/zeit.cms,ZeitOnline/zeit.cms,ZeitOnline/zeit.cms