TSVG duplicate attributes for semi-transparent markers

TSVG::SetColor always appends both fill-opacity and stroke-opacity tags, so you end up with duplicate attributes when both "fill" and "stroke" color are being set.

As far as I can tell SetColor is always called after either a PrintStr("stroke=") or a PrintStr("fill=") so there should probably be two variants, one that sets fill color with its opacity and one that sets stroke color with its opacity. This way you won't get duplicate attributes and invalid svg files.

Attaching an example of invalid SVG and the code used to produce it.