remove use of ob.update_from_editmode() since editmode meshes don't get access to customdata layers. 

Another glitch from recent alpha work. Also modified povray's code. As usual, maintainders of these scripts, please double check changes are ok! :)

make addons blender versions consistent

finished

Note: would have loved to add an option to export tesselated layout (instead of ngon one), but currently I often get mesh without tesselation, and seems there is no way to call ensure_tesselated from python...