[patch] pgsql async query

Since I didn't get much comment/request, so I changed it the way I like. (I'll use zend_parse_parameter() later, since existing functions are not using it yet) - get rid of some functions and made easier to use async query - garbage collection at request shutdown - pg_send_query() changes mode to nonblocking internally - pg_is_busy() calls PQconsumeInput() internally It's much easier to use now. Aync Query Functions: - pg_send_query() - send query - pg_get_result() - get async query result - pg_is_busy() - executing async query or not - pg_request_cancel() - candel currently executing query Misc Functions: - pg_reset() - reconnect to server. Useful when backend is died. - pg_status() - current connection status. README, patch and test script is attached. (Make sure you use CGI bin, set output_buffering=Off and edit database connection parameter. There are some limitations in libpq. You may not be able to execute query asyncronously) Comments are welcome. -- Yasuo Ohgaki