Support all parameters for ldap_search, especially sizelimit and timelimit

My LDAP service is kind enough to honor the sizelimit and timelimit parameters, so this PR may be useful to others.  These extra 4 parameters were added in PHP 4.0.2, so I think it is a safe addition to LdapBundle.

Reference: http://us1.php.net/manual/en/function.ldap-search.php