Change filter definition syntax.
Allow to pass arguments to the execd binary.
Merge branch 'master' into portable

Conflicts:
	smtpd/mproc.c
- fix the parse_attribute interface, it was doing not really smart
- while at it, fix user authentication which was not fetching the correct attribute
Merge branch 'master' of ssh://ssh.poolp.org/git/opensmtpd
Merge branch 'master' into portable

Conflicts:
	smtpd/mproc.c
Merge branch 'portable' of ssh://ssh.poolp.org/git/opensmtpd into portable

Conflicts:
	smtpd/mproc.c