Fixed Search Everything so it searches metadata, slugs, excerps properly

Right now when including excerps in search, then it only matches the complete search sentence and not every single term in the sentence.

Right now when including metadata in search, then it automatically includes pages, even if having configured pages not to be included.

Right now it is not possible to search the permalink-slug.

I have fixed the problem for Search Everything 3.9.9. Please report if the code contains any bugs.

//search excerpts
function SE3_search_excerpt($where) {
   $where = preg_replace("/ OR \(post_content LIKE \'\%([^\%]*)\%/", " OR (post_content LIKE '%$1%') OR (post_excerpt LIKE '%$1%", $where);
   SE3_log("excerpts where: ".$where);
   return $where;
}

//search slugs
function SE3_search_slug($where) {
   $where = preg_replace("/ OR \(post_content LIKE \'\%([^\%]*)\%/", " OR (post_content LIKE '%$1%') OR (post_name LIKE '%$1%", $where);
   SE3_log("slugs where: ".$where);
   return $where;
}

//search metadata
function SE3_search_metadata($where) {
   $where = preg_replace("/ OR \(post_content LIKE \'\%([^\%]*)\%/", " OR (post_content LIKE '%$1%') OR (meta_value LIKE '%$1%", $where);
   SE3_log("metadata where: ".$where);
   return $where;
}