Create CSS rules for the attributes presentation:display-*

Improves the display of many of my test ODP slides :)

Also achieves pretty similar results in LO and the viewer for
https://wiki.gnome.org/GUADEC/2014/LightningTalks/SlideDesign?action=AttachFile&do=view&target=lightning_talks.odp

Once this is in and 0.5.2 out, they will have no excuse not to use ViewerJS for their webpages and even presentations :)
It is not obvious, so rather I need to apologize to not have explained this unusual approach in a comment yet, will be added.
Reason is that the master page actually also references a style... currently it is unclear to me whether the cloned master page should continue to reference the style, or if the style of the actual page should take over... If the cloned page should still reference its original style (what I assume so far, even if I did not yet add code for that), then we need a way to reference the style of the actual page in the cloned master page. Which is what would be achieved by this custom attribute.
Have to admit this is slightly rushing things for felt improvements than a solid polished fix. But the direction should be correct...