Added FTS match :@@ operator

Added a new operator for the Fast Text Search operator @@

Example: 
```lisp
(sql (:select 'id 'name
	      :from 'people (:as (:to-tsquery "english" "john doe") 'ts-query)
	      :where (:@@ (:to-tsvector 'busqueda) 'ts-query)))```
Expands to:
```lisp
"(SELECT id, name FROM people, to_tsquery(E'english', E'john doe') AS ts_query WHERE (to_tsvector(busqueda) @@ ts_query))"```