Revised Chapter 3 of Contributors' Guide

I have revised Chapter 3, Using the ODFAuthors website, and placed it
in the Resources folder and on the wiki.
http://www.odfauthors.org/libreoffice/english/resources-for-contributers/using-the-odfauthors-website/view
https://wiki.documentfoundation.org/images/9/9a/Using-ODFAuthors.odt

--Jean