#3 offer chance to register site when class not found

[Julian Hyde]

If a search fails, should say 'Could not find class
com.foo.Bar. If you know of a site where this class is
documented, please click here to register'.

We could even create a link 'search for a site', as
follows: http://www.google.com/search?hl=en&ie=UTF-
8&oe=UTF-8&q=%22tree+deprecated+index%
22+com.foo.Bar