Backport change from 1.1.13: NEWS,src/cad3d.c,src/export.cc: Fix export to SVG when a label contains a '%' character.
git-svn-id: file:///home/survex-svn/survex/branches/1.0@3459 4b37db11-9a0c-4f06-9ece-9ab7cdaee568