Based on Daniel Groger's work of five years ago, with minor changes
http://www.mail-archive.com/lyx-devel%40lists.lyx.org/msg169820.html
This extends the support for Xfig LaTeX + PDF to a more modern and
actively developed vector graphics editor. Embedded Objects manual
updated, also to include a workaround for an Inkscape 0.91 bug.
