Save as SVG

Hi,

How hard would it be to add support for saving files as SVG? Iperender
apparently supports exporting to SVG, so I assume the SVG-writing code
is already done. And you could pretty easily embed the IPE file data
in the SVG in a <metadata> element, e.g.

  <svg ... xmlns:ipe="...">
    <metadata>
      <ipe:data> ...ipe data... </ipe:data>
    </metadata>
    ...

My use case is making an HTML5 presentation (with remarkjs). It would
be really nice if I could just include IPE diagrams via <img
src="mydiagram.svg"> but as it stands I would have to save them as
.ipe and then run iperender which is a slightly annoying extra step.

Cheers,

Tim