bogofilter-0.16.2 - new current release

[Clint Adams]

> Do not use options with _optional_ argument. Either "mandatory argument"
> or "does not take argument".

I like it the way it is, except for the incompatibility with 0.16.1.
Probably this would have been less surprising if this had been a bump
to 0.17.

However, you could return -u to no-argument and use another option
for the cutoff.  Wastes a letter, but doesn't break .procmailrcs.