Make the scheduler proc backend setuid and chroot by default
prepare code for hanling setuid/chroot in external table backends.
disabled for now since it requires changes in the bootstrapping
Prepare for setuid/chroot in external queue process.
Does not work for now. Need to tweak bootstrapping.
Merge branch 'master' into portable

Conflicts:
	smtpd/smtpd.h
missing include
Merge branch 'master' into portable
only remove the incoming dir if running in server mode
Merge branch 'master' into portable
Document how the default server name is determined
Merge branch 'master' into portable
Show one accept message per rcpt for the same message
Merge branch 'master' into portable
Allow to restrict the address family used for smtp and mta in the
configuration file:

listen on <iface> [inet4|inet6] ...

limit mta [for domain my.domain] [inet4|inet6]
Merge branch 'master' into portable
fix bug in envelope cache
Automatically detect if asr needs to be built along with smtpd
Do not schedule mta envelopes in batch.
Allow individual envelopes to be suspended in the scheduler.
Associated commands are:

smtpctl pause envelope <id>
smtpctl resume envelope <id>
Merge branch 'master' into portable