cleanup error message

dunno what I really wanted back then.
remove -a and one -v, add --partial so that resume works

Tests confirm that resume works now: upon ctl-c (assumption..), it
actually moves over the .$name$tmp file over to $name, even if only
partially done, which sounds like the point of the flag actually, and
hence (even without --fuzzy) continues on that file in the next round.
remove -v altogether
optionally take BWLIMIT env setting ("" for no limit)
add (insecure) --eval option
accept user/cmd/args arguments
create

(recreate, loss on tie)