Minor rendering bugfix

"librsvg-ERROR **: _rsvg_acquire_xlink_href_resource called for external resource: " base: (null)"

This bug appears new to in the past already correct rendered images. One reason can be a missing <def /> (I don't work with bugzilla, this bug is not mentioned there) Examples commons:File:Destruenten_im_Stoffkreislauf.svg[1] --Perhelion (talk) 20:15, 12 January 2011 (UTC)

My correction: another reason can be a missing or incorrect marker in <def> and a &quot; (as ' ) in CSS code by Inkscape bug.