- the render script language is simplified by stripping 'draw-' and
   'fill-' prefix to rendering command. The draw or fill must be used is
   deduced from the attributes 'fill' and/or 'stroke'
 - import from rendering command finally got implemented as a fallback for
   unknown object types
 - no more G_GNUC_UNUSED necessary, everything is used and debugged now;)

To test the new rendering import either some object plug-ins used for creating
a file need to be disabled or the object type needs in the exported file need
to be renamed.