[dns-operations] dnscap update

[Paul Vixie]

i've removed the 'e' argument from '-m' and added a new '-e' option whose
arguments are [yn].  errors just aren't a message type.  see anoncvs, with
instructions at <http://public.oarci.net/tools/dnscap/>.

next up: ip reassembly for edns responses that come in fragmented.  but we
might want to declare V1.0 if we're sure that the command line syntax has
stopped morphing every week.

(actually, next up will be epoch-based timing, so that rather than just -t
3600 it'll be possible to say "every hour on the hour" even if that makes
the first dump file shorter than the rest.  and that'll be a CLI change.)