Redundant information, but makes the journal easier to read. The
redundancy might help making a journal replay tool robust.
Put it in Hvy Metal II now to gather some real data.
(journal_reopen): New.
(main): Use it. Fixes failure to obey !keep_journal.
(journal_open): Internal linkage, changed semantics and return value.
Callers changed.
(journal_close): One caller left, inline and remove.
(keep_journal): New econfig key.
(player_main): Log player login and logout.
(recvclient): Log player input.
(ef_open_srv, ef_close_srv): Log startup and shutdown.
(update_main): Log update.
Support the common SIGHUP log rotation idiom:
(empth_wait_for_shutdown, empth_wait_for_signal): Rename.
[EMPTH_LWP, EMPTH_POSIX] (empth_init, empth_wait_for_signal): Wait for
SIGHUP as well.
(main) [SIGHUP]: Reopen journal when empth_wait_for_signal() returns
SIGHUP.
