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 :)
Ahh... indeed! I didn't realise a master-page had a style-name itself. One small suggestion would be to change this to 'page-style-name'. A comment as to why style-name can't be used would help as well :)