re-parse in the backend. Keep track of pagedresult controls and state
in backglue.

now unifdef'd.

  store conn->c_sd, don't use ber_sockbuf_ctrl to retrieve it.
  use per-thread free lists for operations, no mutexes needed.

Finish port of rfc4511 into appendix for error codes. Just need to give examples as to why a user would hit a certain error in relation to a slap*/ldap* tool