Updated links, deleted solved entries, added to reasoning, prioritized some problems.

My original intention was just to add an entry about the circular definition of article as "defines an article" and section as "defines a section", but when I got in there I found lots of wild & wooly things, marked various problems as <del>solved</del> and tried to prioritize some of the more systemic issues to the top and <del>solved</del> issues to the bottom.

One quite interesting thing that I found is that the w3schools site now has a "REPORT ERROR" link in very tiny text in their footer.  I suggest we begin to use it liberally to report many of the various problems found on the w3fools site, and see if they do anything about it.