Fix SVG format

[peteruithoven]

Vivicut doesn't load the export svg's. When I add the following to the top it does.

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">