[swfmill] SVG support committed

[Ralf Fuest]

Hello,
I've just committed the new SVG support to the SVN. It's a huge change
to the swfmill code and I hope I haven't broke anything, so please test
as much as you can.

There are some improvements to my older patch:
- polyline and polygon tags are supported
- spreadMethod is supported
- radial gradients with focal point
- added a "-n" parameter to swfmill wich disables libxml network access.
  This speeds up svg conversion, because libxml doesn't fetch the DTDs
over the net anymore.

Ralf