More log message overhaul. POP3 CAPA cmd support in transaction state.

Log the IP address first in most log messages.
Condense white-space in log messages to a single space.
Log the server IP address of incoming connections.
(more) Intelligent email address enclosure in angle-brackets.
Better duplicate address comparison (just for log message).
Fix wrong order of lprintf arguments in !UNKNOWN USER log message (new bug).