SVG output file size reduction

[PCJ]

The SVG output format support uses absolute positioning which creates significantly larger output files. In the interest of reducing bandwidth the polyine and polygon support should be changed to use relative positioning through the path SVG object (ie. use M as the poly anchor and subsequently l for relative move line-to operations). I've attached a modified file that does this.

Further improvements could be made, but I haven't look into it in detail, by using def embedded CSS styles into the SVG output so that common object attributes could be replaced with a single style reference. In that way much of the repeated content (ie. replace 'fill="none" stroke="#9326ff" stroke-width="1"' with 'style=blah') can be removed, once again reducing the SVG file size.

Paavo.