Allow author.php to show even if author has 0 posts.

[ruckerz]

Loading /author/username will return a 404 if author has no posts. It is desirable to show something, in my case, author profiles and let author.php decide what to do if the author has 0 posts.

Rewrote handle_404() to...

if ( (0 == count($wp_query->posts)) && (!isset($wp_query->query_varscat?)

$wp_query->query_varscat?== 0) && (!isset($wp_query->query_varsauthor?)

$wp_query->query_varsauthor? == 0) && !is_404() && !is_search() && ( $this->did_permalink

(!empty($_SERVERQUERY_STRING?) && (false === strpos($_SERVERREQUEST_URI?, '?'))) ) ) {

Note this includes patches from Trac #1969 (Check for category and author page existence) and also solves final comment by _ck_.

#3345