Remove CC0 button from Web page

Remove CC0 button from Web page

A couple of reasons.  Firstly, being hosted externally it was an
unnecessary privacy leak.  I could have included it in the
distribution (and thus hosted it myself), but it would have perversely
been the least free thing in there.

Secondly, its colours jarred with the rest of the page.  If the button
were free, I could adjust its colours to match the rest of the page,
but it's not and changing its colours isn't allowed.  I did wonder
about playing games with CSS filters, but that would be complicated
and not really in keeping with the spirit of the licence.

Given both of those, removing it seems like the simplest approach.