Implemented --fork
Implemented support for --restore and --status for --fork'ed sessions
Send SIGUSR2 to child processes on a keypress, and have them print status upon
receipt of this signal
Prefix the status line with node number when running a --fork'ed session
Print the status line to stderr all at once, not piece by piece
Unlock the .rec file before closing it when we intend to re-open the file for
writing and lock it again.  This appears to help avoid a race condition on
Linux where a subsequent rec_lock() would fail (flock() failing with
EWOULDBLOCK) if too little time elapses yet the process happens to be bounced
to a different CPU.
Prefix log file lines with node number when running a --fork'ed session
Don't try to signal the (non-existent) child processes when we're not --fork'ed
1.7.9.12:
The --fork=N option has been added