[Vimoutliner] patch: allow progress items with no children

[Scott Scriven]

* Noel Henson <noel at noels-lab.com> wrote:
> Thanks! I've been meaning to get to that. Been bogged down with
> work. I'll patch mine and test it. If it works as advertised,
> I'll include it in the next release.

Using it today, I've already noticed one more change it needs.
The check/uncheck function should set the percent to 100% or 0%
instead of ignoring the line.  But I'll see about changing that a
bit later.  :)


-- Scott