Export to SVG incorrectly exports some characters.

[wvdvegt]

When I export a graph containing certain characters , the SVG won't load/display in for example Microsoft Edge.

See #351 for screenshots of the text used.

In the LabelTest the following characters are not exported properly:

• '&' Should be exported as '&' as SVG is an xml based format.
• '<' Should be exported as '<'.
• leading spaces (use for simple indent) should be exported as '&# 160;' (as '&nbsp;' fails with an xml error as well).

FYI I was able to correct the '&' and '<' issue by supplying a nodeSanitizer to the SvgGraphWriter.Write() method.

Func<string, string> nodeSanitizer = s =>
{
return s
	.Replace("&", "&amp;")
	.Replace("<", "&lt;")
	.Replace(" ", "&#160;");
};

[levnach]

Should your change be a part of the default sanitizer? If so, please create a pull request.

[wvdvegt]

Not confortable enough with the code to make such changes & pull requests.

I was unware there was a default sanitizer at all. Did you mean the code in WriteLabelText()?