Add a conformance section.

Closes https://www.w3.org/Bugs/Public/show_bug.cgi?id=22591

Let me know if you think this is sufficient.
I would like to run format.py on all the file and make all indentations etc uniform. You can do that now.
However, I may go through and fix up those lines where an inside attribute value received a line break, because that is really hard to catch when doing search and replace.
That should not stop you from applying format.py though! It's not like currently all inside attributes don't have  aline break!