update for 6.60

*file* mailer flags changed

add ListenQueueLength daemon option keyword

document O8 => O7 change, j (MIME Encapsulation) option, expanded A option

document b and g mailer flags

6.55 features; list of contributors

B line in qf file

add fifth parameter to *_map_lookup

document multiple hostnames on IPC $@ clause and IDENTPROTO
compile flag

fix documentation of -f in map specifications

clarify what IDENT does -- and does not -- do

document IDENT, including limitations

document $&x

document $_ and Directory=

add O and V options

$~ reverts to only matching one wor

add multi-word classes to the V6 CHANGES section

classes can be multiple words

dequote map class

use NETINET instead of DAEMON to compile in internet support

document F line in qf file

document enhanced T option

document new longer queue ids

delete $<

clarify use of $@ in local address resolution