Conditional role link

[prushforth]

Make role="application" or role="link" attribute of featureGroup conditional on whether the graphic is a link or simply a popup.

@Malvoz I noticed that links were not being announced. I think this resolves it, or improves the experience a little.

[Malvoz]

Where can I test links? I know we have featureLinks.html but that uses <map> so that's not going to be accessible in all browsers no matter our efforts.

[prushforth]

A couple here, I'll add another example

http://maps4html.org/experiments/painting/

[Malvoz]

In my testing NVDA announces: Graphic, Girl zoom equals 2, Link.

If role="none" (and space separated/or presentation, these are synonyms, latter is legacy role) is set on the parent <svg>, it is not announced as Graphic and the output is: Girl zoom equals 2, Link which I think is more appropriate.

Or maybe we want Graphic to be announced? I guess it's not inaccurate.

[Malvoz]

Just noted that there's a comment that probably should be removed. Other than that LGTM!