This is a resend since I note that zsh-users do not get the content from zsh-
workers and I would appreciate the feedback of any zsh-users who use ipset in 
their ZSH life :)

The attached patch fixes competion in zsh for the current iterations of ipset.

When embarking on this task, I had hoped to also add the "arg-less" commands 
that ipset now accepts, but unfortunately my zsh-fu is not quite there yet it 
seems and so this patch retains solely the hyphenated argument syntax.

Regards,
Oliver