POP3

RFC ???

I. Authorization State
- USER / PASS
- APOP
- AUTH (proposed - 1734)

II. Transaction State
- STAT
- LIST
- RETR
- DELE
- NOOP
- RSET
- TOP  (message #, # lines in body)
- UIDL (unique identification listing)
- QUIT (Goes to Update State)

III. Update State
- Deletes all messages marked for deletion.