Change VIMUSERS first headline to use toc-org package
Change VIMUSERS first headline to use toc-org package

As this includes 4 levels of headings, the tag that needs to be used is
:b9c4b8887d9b67e2b035e1fdc4438043f729625d@4:. Now every time one saves this file, the TOC is automatically
generated. There is an interesting feature from toc-org that enables
users to use org links or GitHub enabled
[links](https://github.com/snosov1/toc-org#use)
 we should discuss how to use it because on one hand, having org links
 makes it easier to read in emacs, while having GitHub links makes it
 easier to read online.

tsonntag/dotemacs,tsonntag/dotemacs,tsonntag/dotemacs,tsonntag/dotemacs