Add place to put link to demo

[ewinslow]

Sometimes nice to get even more than screenshots -- links to live demos are cool, especially for themes

[mrclay]

I'm ok with this but I almost never find demos in working order, and with Elgg you generally can't do a lot logged out.

[juho-jaakkola]

I almost never find demos in working order

Let's add a button for reporting a broken demo. The demo link becomes hidden until plugin maintainer fixes the demo and enables the link again.

[Srokap]

@juho-jaakkola Sound's like a thing to be done via reported content form. Could add special link for it that would suggest an option.

[ewinslow]

I think this would be better covered by #31

[juho-jaakkola]

@Srokap Reports made via reported content go only to the site admins. I was thinking about informing the plugin author instead. (And also hiding the link since there are so many abandoned plugin projects where the author is not around anymore.)