Custom fonts are supported but in a very rudimentary way. Note: if you don't see the demo working,
click "Save as PNG" - it should work.
Make sure that the custom font is applied to a non-svg element first. This will help browser to rasterize SVG correctly onto canvas.
@font-face declaration has to be inside document stylesheets (not in the external `link` tag)
Only first `url()` is inlined into svg (don't have multiple urls in the font-face).
